The A.B.-Z. of our own nutrition

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Title: The A.B.-Z. of our own nutrition
Author: Fletcher, Horace
Language: English
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NUTRITION ***

Transcriber’s Notes

Obvious typographical errors have been silently corrected. Variations
in hyphenation and accents have been standardised but all other
spelling and punctuation remains unchanged.

Italics are represented thus _italic_ and bold thus =bold=.

THE A. B.-Z.

OUR OWN NUTRITION

HORACE FLETCHER’S WORKS

THE A. B.-Z. OF OUR OWN NUTRITION. 462 pp. Just issued.

THE NEW MENTICULTURE; OR, THE A-B-C OF TRUE LIVING. Fortieth thousand.
310 pp.

THE NEW GLUTTON OR EPICURE; OR, ECONOMIC NUTRITION. 324 pp. Just
issued.

HAPPINESS AS FOUND IN FORETHOUGHT MINUS FEARTHOUGHT. Tenth thousand.
251 pp.

THAT LAST WAIF; OR, SOCIAL QUARANTINE. 270 pp.

_The_ A. B.-Z.
_of_ OUR OWN
NUTRITION

_By_ HORACE FLETCHER
_Author of “Menticulture,” “Happiness,” “That
Last Waif,” “Glutton or Epicure,” Etc., Etc._

EXPERIMENTALLY ASSISTED BY
DR. ERNEST VAN SOMEREN,
M. R. C. S., L. R. C. P., _of Venice, Italy_
& DR. HUBERT HIGGINS, M.A.,
M. R. C. S., L. R. C. P., _of Cambridge, England_

_NEW YORK_ ‧ FREDERICK A.
STOKES COMPANY ‧ _PUBLISHERS_

Published November, 1903
Reprinted February, 1904, August, 1904
February, 1905, August, 1905

THE UNIVERSITY PRESS
CAMBRIDGE U. S. A.

CONTENTS

Page
INTRODUCTION ix

POSTINTRODUCTORY xxvii

THE A.B.-Z. PRIMER

Explanation 3

Some Pertinent Questions 4

A.—The Psychology of Nutrition 6

B.—The Mechanical and Chemical Physiology of
Nutrition 8

Method 9

Z.— The True Chemical End-Point of Digestion 10

A.B.-Z. Figure 12

Preface to 1906 Edition 13

HISTORY OF DEVELOPMENT AND SUPPORTING
EVIDENCE

Summary of the Foregoing Pages by an Experimenter
of One Month’s Experience 19

First Scientific Recognition of the Principles of
Economic Nutrition Outlined in “Glutton or Epicure.” H.F. 26

Was Luigi Cornaro Right? by Ernest Van Someren 27

The Cambridge Tests.H.F. 47

Experiments upon Human Nutrition, by Sir Michael
Foster, K.C.B., M.P., F.R.S. 48

Report of a Plan for the Institution of an International
Inquiry into the Subject of Human
Nutrition.H.F. 53

Proposal to Found an International Laboratory of
Research for the Study of Nutrition in all Its
Aspects. Recommended by the following 55
Professors of Physiology, etc.:

Sir Michael Foster, Cambridge, England.
Angelo Mosso, Turin, Italy.
Hugo Kronecker, Bern, Switzerland.
N. Zuntz, Berlin, Germany.
Paul Heger, Brussels, Belgium.
A. Dastre, Paris, France.
Henry P. Bowditch, Harvard Medical School.
Russell H. Chittenden, Yale University.
William H. Welch, Johns Hopkins University.
J.P. Pawlow, Saint Petersburg, Russia.

Nationality and Scientific Titles of the above Board
of Scientific Assessors 68

Persistent Scientific Doubts.H.F. 69

Physiological Economy in Nutrition, by Professor
Russell H. Chittenden 72

Introduction to Dr. Harry Campbell’s Contribution
on the Importance of Mastication.H.F. 92

Observations on Mastication, by Harry Campbell,
M.D., F.R.C.P. 96

Introduction to Professor Pawlow’s Demonstrations
of Psychic Influence in Digestion.H.F. 180

Selected Lectures by Professor J.P. Pawlow (Dr.
W.H. Thompson’s translation) 182

Lecture IV.: General Scheme of an Innervation
Mechanism--The Work of the Nervous Apparatus
of the Salivary Glands--Appetite, the First
and Most Potent Exciter of the Gastric Secretion 182

Lecture V.: Period of Occurrence and Importance
of the Psychic or Appetite Juice in the Secretory
Work of the Stomach--The Inefficiency of
Mechanical Stimulation of the Nervous Apparatus
of the Gastric Glands 212

Lecture VIII.: Physiological Action and the Teaching
of Instinct: Experiences of the Physician 247

Introduction to Dr. Cannon’s Papers on Movements
in the Alimentary Canal studied by Means
of the Röntgen Rays.H.F. 284

Swallowing and Movements of the Stomach and
Intestines, by W.B. Cannon, M.D. 285

The Movements of the Food in the Œsophagus,
by W.B. Cannon and A. Moser 285

The Movements of the Stomach, by W.B. Cannon 301

The Movements of the Intestines, by W.B. Cannon 342

The Battle Creek Laboratories.H.F. 389

Experimental Investigation of the Influence of
Mastication and Cooking of Food, etc., in the
Laboratories of the Battle Creek, Michigan, Sanitarium,
under the direction of Dr.J.H. Kellogg 391

Dr. Edward Hooker Dewey and the “No Breakfast
Plan.” H.F. 396

Professor Jaffa and the Fruitarians.H.F. 397

Dr.H.P. Armsby.H.F. 397

Explanation of the A.B.C. Series.H.F. 399

INDEX 409

INTRODUCTION

_DO WE EAT TOO MUCH?_
CAN WE LEARN TO EAT RIGHT?
WITHOUT LOSS OF ENJOYMENT?
WITHOUT CARE BEING A NUISANCE?
WITHOUT SOCIAL INTERFERENCE?
WITH ASSURANCE OF HEALTH?
WITH INCREASE OF ENERGY?
WITH INCREASE OF ENDURANCE?

* * * * *

TO ALL THESE VITAL QUESTIONS,
THIS BOOK ANSWERS ONLY “YES.”

* * * * *

VERIFY THIS BY PERSONAL EXPERIMENT.
IRRESISTIBLE DESIRE FOR PHYSICAL EXERCISE
WILL FOLLOW, AS A MATTER OF COURSE,
PROBABLY FRUITING IN USEFUL ACCOMPLISHMENT
BY THE SAME INVITATION OF HEALTHY IMPULSE
WHICH CAUSES CHILDREN TO PLAY TIRELESSLY.
DO RIGHT YOUR FEEDING OF THE BODY.
NATURE WILL DO ALL THE REST FOR YOU ARIGHT.

Introduction

DO WE EAT TOO MUCH?

(_A propos of the Scientific-Military Experiments at Yale University_)

Do we eat too much?

Nine out of every ten physicians tell us “Yes,” and tell us true!

How much too much?

* * * * *

Luigi Cornaro suggested that all persons in his time ate more than was
necessary; most persons ate twice as much as was good for them; and
some, who were extravagantly gluttonous, ate ten times as much as was
their most economic need; and Cornaro, who was a dissipated wreck at
forty, reformed his manner of eating and lived to be a hundred to prove
his declaration.

Experiments carried on in this country and in Europe during the
past five years confirm this estimate of habitual excess; but
fortunately they have also revealed a natural protection, heretofore
unappreciated, available to all, which can regulate the appetite to
suit the real needs of nutrition and thus avoid the dangerous excess
which predisposes to discomfort and disease.

* * * * *

Luigi Cornaro lived more than three hundred years ago. His charmingly
frank and interesting autobiography has been published in English
upwards of forty times in different new editions, and no one has
disproved the possibility or probability of his claim. We all know that
Cornaro was right. We know, in a general way, that the great Italian
dietitian and philosopher was wise and uttered wisdom, and we are told
that most, if not all, of the diseases which pain, worry, and afflict
us are caused by indigestion or mal-assimilation of food, the result
of some indiscretions of eating. The questions then are “What are our
indiscretions?” “How can we avoid them?” and “What is the new discovery
that will protect us and, at the same time, add to the pleasures of the
palate and of living?”

The answers to all these queries will be found herein, as will also
an explanation of the very active interest which is being taken just
now in the problem of human nutrition by scientific and military
authorities, as evidenced by the Yale investigation.

The author has, in collaboration with several others, found a way how
_not to eat too much_ while eating _all that the appetite desires_, and
in a way that leads to a _maximum of good taste_ and at a _minimum of
cost and waste_, but it is necessary to test many persons of different
physiques and varying temperaments, and also to test other methods of
attainment of economy, to learn what is best for general application,
and that is what is being done at Yale.

* * * * *

The cost to the pocket that is saved by economic nutrition is of little
matter as compared with the saving of the waste of energy and the
menace of disease.

* * * * *

Nature certainly never intended that we should weaken, depress, and
distress ourselves in the way that is common to present-day living, as
is made evident by the prevalence of discomfort and disease relative
to our daily food. Nature’s plan of evolution does not work that way
in general, does not retrograde in the progress of the improvement
of plants and dumb animals, and certainly does not intend that Man,
the First Assistant of Nature in the cultivation of things and in the
domestication of the powerful natural forces, should suffer and become
degenerate contrary to her general law.

If we are agreed upon the foregoing, let us ask ourselves a few
questions.

Without any undue egotism, may it not be possible for a generation of
human beings, who have progressed so far in intelligence as to be able
to move things by steam, to communicate across the ocean even without
wires to guide our messages, and to see clearly through objects that
are as dark as night to the unassisted human eye with the aid of an
artificial light, to learn the secret of right self-nutrition and
practise it in a manner that will not deprive us of the maximum of
pleasure which Nature invariably gives as a reward for conformity with
her beneficent requirements? May we not assume that beings who have
learned to breed and train horses to race with human intelligence, and
to run, trot, or pace a mile in less than two minutes, may also train
themselves to have the proportional relative speed, endurance, and
longevity that has been attained by race horses through man’s care,
and to enjoy the pleasure of living that is evident in these favoured
animals, mere servitors of man though they be?

If this disparity of man is due to ignorance arising in self-neglect,
which is the usual accompaniment of genius, may we not now, at the
beginning of the pregnant twentieth century, rest for a moment from
discovering, developing, and improving the world outside our personal
selves and concentrate our attention for a while on learning to know
and care for ourselves? May we not, at least, give “horse sense”
attention to such a vital interest?

* * * * *

In the midst of the present confusion which exists among opinions as to
the right conduct of life and activity, and the best manner and system
of diet to be used to secure health and efficiency, it seems almost a
vain appeal to call for concert of action in a matter of common and
persistent neglect. Each person, as his own keeper, is careless, and
in matters of bodily management no one feels called upon to be his
brother’s keeper; but this is merely the lethargy of oversight and
consequent ignorance, and this book is published to call attention to
the oversight and to attempt to dispel the ignorance.

* * * * *

At the present moment of writing (October, 1903) there are quartered
at New Haven, Connecticut, twenty privates of the Hospital Corps of
the United States Army and three non-commissioned officers, under the
command of Assistant Surgeon, Lieutenant Wallace DeWitt. These men
and officers, while they are under regular army discipline and are
performing duty in conformity with their oath of enlistment, are yet
volunteers. They are from the same corps, if they are not the same
men, which furnished volunteers to investigate the causes of yellow
fever in Cuba, whose heroism resulted in stamping the fever out of the
islands and in that more effectually protecting our coast states from
its yearly incursions. These are the same men who generously refused to
accept the offered bounty. This latter expression of exalted manhood is
evidence of what humanity is whenever there is real need for heroes to
serve the general good. They refused to _sell_ themselves as risks for
money, but they freely _offered_ themselves as subjects of scientific
investigation for the benefit of their fellows and of mankind at large.

* * * * *

The duty that the soldiers are engaged in at Yale has no element of
risk, and need not have any feature of monotony or tediousness in
it, much less has it the romance of sacrifice, for it deals with an
attempt to restore normality and does not consort with disease. But the
service being rendered by these guardians of our health, these soldiers
of hygiene, is even more important than was the service rendered in
stamping out yellow fever, for it deals with an enemy much more
subtle, treacherous, common, and deadly than Yellow Jack. Yellow fever
calls for a halt and an immediate attempt at cure, and further, for
stringent defence to extermination; but indigestion and the American
plague, _dyspepsia_, work their evils slowly but surely to cut off our
best men and loveliest women in their prime and to rob us of their
richest product and of their maturest wisdom.

* * * * *

The investigation at Yale is a link in a chain of effort that has
developed in logical sequence and has been planned to effect a cure of
the common ignorance and practice relative to right human nutrition in
its relation to profitable thinking and doing; and to discourage the
personal neglect which has been responsible for the existing ignorance,
this book is issued to show what may easily be done and what has been
done, so far, in this direction. It is a compilation of important
knowledge which has been born of recent scientific research but which
is hidden away from common comprehension in scientific publications;
and it relates the story of the development of which this book is an
exponent. Herein are given the reasons why the government and the
most eminent scientists in the line of researches in nutrition are
coöperating so earnestly and so unusually in a commonweal inquiry.

* * * * *

About ten years ago, at the critical age of forty-four, the author was
fast becoming a physical wreck in the midst of a business, club, and
social tempest. Although he was trained as an athlete in his youth
and had lived an active and most agreeable life, he had contracted a
degree of physical disorder that made him ineligible as an insurance
risk. This unexpected disability, with such unmistakable warning, was
so much a shock to his hopes of a long life that it led to his making
a strong personal effort to save himself. The study was taken up in
systematic manner, account of which is too long to relate here; but the
eager auto-reformer soon learned that his troubles came from _too much_
of many things, among them too much food and too much needless worry;
and realising the danger ahead, he sought a way to cure himself of
his disabilities by the help of an economic food supply, as did Luigi
Cornaro; but what is even more important, he found a way to enjoy the
smaller quantity of food much more than any plethoric luxury can give,
and arrived at the method by a route that showed a means of conserving
a healthy economy and an increased pleasure of eating, at the same
time, in quite a simple and scientific manner, that any one may learn
and practise without any ascetic deprivation whatever. Cornaro buried
the real clew to his economic and pleasurable success with his body,
owing to his vague generality of description of his method. The author
is determined not to make the same mistake, and thereby bury _his_ key
to a happy and easy life.

* * * * *

The secret of the method is all told in this book and is confirmed
herein by both theoretically scientific and scientifically practical
authority; but the experiments which are being conducted at Yale by
Professor Chittenden, in coöperation with Surgeon-General O’Reilly of
the army, of which the _Daily Press_ has given notice, together with
experiments which are in progress in many university laboratories in
this country and in Europe, are for the purpose of explaining the
“reasons for things” by complete scientific reasoning, so that none may
doubt the disadvantage and sin of dietic ignorance and carelessness.

The acceptance of the theory and method of the author at the great
Battle Creek Sanitarium, after more than a year’s trial, and elsewhere
among curative agencies, and their adoption and use as the first
requisite of treatment, of which the public have not so generally
heard, are indorsements coming from practical, intelligent, and expert
sources of experience and judgment, and hence they are of the utmost
value and significance.

* * * * *

This introductory chapter is being written after the “clippings” of
newspaper comment relative to the presence of the soldiers at Yale have
begun to come in. The majority of comments are generous in spirit, but
indicate a lack of complete understanding which this “Introduction” is
intended to correct.

* * * * *

Some of the comments are couched in ridicule, and express pity for the
poor soldiers who are being “misused” as subjects of starvation in an
investigation which promises to make starvation a rule in the army. To
the writers of such trifling and unfair paragraphs let me, one of the
fraternity in an amateurish way, beg consideration of the following.

The campaign that has been started is against a common enemy of
mankind, and of the American and English nations in particular. In our
successes in agriculture, manufacture, and commerce we have cultivated
insidious, luxurious temptations which bring all of us some ill and
many of us, or our loved ones, fatal disease and premature death. The
advance agent of these enemies of ours is Eating-and-drinking-too-much.

* * * * *

The officers and men of the army and the eminent scientists of our
country and those of all nationalities who have entered into the
campaign with us, and the great power of the sanitaria joining as
practical nurses, demonstrators, and exponents of the reform, are all
working for you and for everybody. It is voluntary service and has
already cost some of the volunteers much time and patience and also a
considerable sum in money.

* * * * *

You, gentlemen of the Press, wielders of the helpful or careless pen,
have a conspicuous pulpit and a far-reaching influence. No one can
escape you. In the search for the news of the day you are encountered
at every turn in your editorials or your paragraphs. In this campaign
we need your assistance to make the coöperation between the army and
science easy and effective. They are too busy working for you and your
best interest to stop to argue to correct your misunderstanding, but
the cause will feel the benefit of your assistance.

Encouragement has powerful influence in stimulating effort and also in
creating and conserving conditions in which men may “do their best.”
What we are trying to learn is, what man _may_ do, under favourable
conditions of knowledge and confidence, to relieve his body of the
_strain of energy-taxing labour_ in disposing of the waste _which any
excess of food imposes_. It is a constructive experiment and not a mere
statistical measurement. Appreciation and applause assist; doubt and
ridicule obstruct.

The soldiers and physiologists are too busy studying indigestion and
possible proteid poisoning and what-not-other causes of intemperance,
disease, and suffering to ask you to assist in spreading only serious
report and right suggestion relative to the importance and purport of
the investigation, but it is my privilege to ask it for the general
good.

* * * * *

Just another word of introduction and then will follow some
_postintroductory_ coincidences relative to the work in hand, and then
an attempt to lay out a ten-page chart of the personal responsibility
in the care of the body and the nourishment of the mind by aid of an
economic and most satisfactory nutrition, so as to make conservation
of energy as easy as possible and life well worth the living. The
scientific support from the pens of professional observers is, however,
the real meat of the book, for which compiler and reader alike are and
should be grateful.

* * * * *

In serving in the humanitarian ranks in a commonweal campaign one
should not need to use the concealment of modesty, nor should he fail
to speak with all frankness. What are the motives behind all this
energy to reform the eating habits of the people? The question has been
so often asked that it is better thus publicly answered.

No one concerned in the campaign has any personal monetary interest
in any kind of food, prepared or otherwise. The movement began in a
suggestion carried by an accidental word given to the author by a
friend, an old-time friend in Japan, and a friendship never to be
forgotten, as related in the author’s book “Menticulture.” Pursuit of
menticulture led further to the discovery that the best mental results
could not be accomplished in a body weakened by any indigestion, any
mal-assimilation of nutriment, any excess of the waste of indigestion.
Then came the quest for the causes of mal-nutrition, which were soon
found, by study of the natural sequences and by going behind the
hypotheses of text-book authority, to arise in the careless ingestion
of food, its neglect in the mouth, and the consequent glut of
unassimilable excess within the body, necessitating enormous expense
of brain and body energy to get rid of the excess.

When the secret of the potency for good of a rationally economic
alimentation was revealed to the author, was confirmed by several
colleagues of different ages and both sexes, and was tested by work
and endurance measurement, and also by the test time, it became
necessary to have given to it the indorsement of highest authority
in order to have the information credited. The new rediscovery was
a simple matter, something everybody thought they knew all about
because it had been under their nose all their life and was one of the
commonplaces of every-day living, but for that very reason it failed
to receive credence, and the backbone of the doubt was habit--lifelong
habit--and this was hard to break even in those who accepted the theory
of economic nutrition as a logical conviction. It was also necessary
to prove that it was not personal idiosyncrasy that favoured us, its
advocates.

It is in pursuit of the latter desideratum that the officers of the
army, the scientists, and the great humanitarian health-restoring
institutions have entered upon conclusive investigations, each in
their own way, to chart out a law of economy that will be generally
applicable and which, it is hoped, can be understood by kindergartners
and mothers for the benefit of the present and of coming generations.

* * * * *

It was just stated that no one concerned in the inquiry was interested
in any food product or in any personally profitable business concern,
and mention of the Battle Creek Sanitarium, so widely known as the
pioneer in fostering the pure food and prepared-cereal manufacture,
may cast a doubt upon the matter in the minds of those who do not
know that the Sanitarium organisation, in its every department, is a
philanthropic, humanitarian institution. It is the parent and feeder of
the American Medical Missionary Cause, which already has established
branches in something over sixty localities situated in or near large
cities in different parts of the world, chiefly America. By perpetual
charter all the profits revert to the spread of the work and the
employees serve for a mere pittance, deriving their major compensation
from enjoyment of the altruistic work.

* * * * *

The old prejudice against the human race which declared that “everybody
had an axe to grind,” that there was “a nigger in every woodpile,” and
such like slanders, must be modified in the light of recent altruistic
development. Altruism has always been existent and had a great new
birth with the beginning of our era, but it was never before so frankly
put upon a business basis as it is now, and this is fast being applied
to every department of business activity. It is now done, not in the
name of any particular creed or cult, or for future reward, but because
_it pays_--first, last, and all the time.

* * * * *

In the study and pursuit of menticulture the author has found that
working for the common good is as necessary to happiness as working for
self, and that the retroactivity and reciprocity of the idea multiplies
the profits indefinitely.

The sequence of profitable, altruistic interrelation is stated in the
“Explanation” of the chain of the A. B. C. Life Series, of which this
book is one of the links.

* * * * *

Aside from those actively engaged in the several investigations to whom
reference is often made, the author wishes to express special gratitude
to Sir Michael Foster and to Professor Henry Pickering Bowditch of
the Board of Scientific Assessors. Unselfish and unremitting in their
assistance and encouragement, the author’s work has been made easy
since their interest was enlisted.

Sir Michael, as Member of Parliament in England, and as a physiological
savant, knows that economic nutrition is the key to England’s welfare,
as well as the basic necessity of temperance, morality, health, and
efficiency, as is expressed in the two documents from him reproduced
in the “Report of a Plan for an International Investigation into
the Subject of Human Nutrition” and in his “Note” on the Cambridge
examination of the author and Dr. Van Someren at Cambridge University
laboratories, given herein.

Professor Bowditch, as a distinguished physiologist, publicist, and
especially as the President of the Children’s Aid Society, of Boston,
Massachusetts, often mentioned as the model institution of its kind
in the world, realises that the effort of the author to secure basic
knowledge relative to right nutrition, adaptable to kindergarten
teaching and home training during the impressionable period of youth,
is of the greatest importance in social reform.

A trial suggestion relative to ways and means of _beginning right_ with
_all the children_ and thus insuring a regeneration of the classes most
in need of reform, in not longer than two decades, is outlined in the
author’s appeal for the waifs of society, entitled “That Last Waif; or
Social Quarantine.”

Whenever there is any disposition to slack up in patience or enthusiasm
to accomplish the ultimate end aimed at, the picture of the waif
in that story is flashed back by memory, and there can be neither
forgetfulness, indifference, nor repose until “that last waif” has been
given _at least a chance of choosing_ between the right and the wrong,
the good and the bad.

POSTINTRODUCTORY

[Just before “going to press” the author has received a letter from
his esteemed colleague, Dr. Hubert Higgins, giving the gist of
interviews with an eminent European physiologist and with a famous
American chemist and dietitian, which so well describes the attitude
of the scientific mind towards the problem of human nutrition that the
scientific mentor of the writer advises its addition to the book.

By the same post there arrived a letter from Dr. J. H. Kellogg, the
life and director of the Battle Creek Sanitarium, expressing practical
appreciation, the result of demonstration, of what is being done to
solve the problem.

Eliminating the personal element and keeping the ultimate object in
view, these communications are coincidentally _a propos_ and intimate
to our “Introduction”; hence their reproduction here.

Numerous other letters and extracts from communications received by the
writer, bearing upon this subject, from the above and other sympathetic
friends are reproduced in “The New Glutton or Epicure,” a free and
easy companion of this book, intended to appeal to a variety of readers.

When it is known that the proceeds of all the publications of the
author are dedicated to the promotion of the objects they advocate,
reference to them or advertisement of them cannot be considered
inappropriate.—HORACE FLETCHER.]

EXTRACTS FROM DR. HIGGINS' LETTER

PALAZZINA TASSO,
CAMPO S. POLO,
VENEZIA.

October 3, 1903.

DEAR MR. FLETCHER,--A. appears to me to have an exceedingly broad and
philosophic grasp of the problem of nutrition.

He recognises that all present data are subject to criticism, and that
there are no scientifically accurate data available because

(_a_) Observations are taken over too short a period.

(_b_) They have mainly dealt with one side of the problem,--the output
of muscular work.

(_c_) The observations are not sufficiently complete.

He acknowledges that cleavage products from food broken down in the
intestines by bacteria are the cause of

(_a_) Inefficiency
(_b_) Diseases
(_c_) Mental derangements.
(See Mott’s work.)

He recognises that the majority of people eat far too much. He puts
this in the following way. If a “mediæval devil” had wished to discover
the most subtle and most effective way to destroy mankind mentally,
morally, and physically, he would have arranged for them to be supplied
with tasty, well-cooked foods, wines, etc.; in short, he would have
used every means to tempt, confuse, and pervert their appetite. He
would also have arranged every possible means to prevent their being in
the fresh air and taking exercise. He thinks one has here the picture
of modern civilisation.

He talked in a very interesting and instructive manner about the
necessity and value of exercise and a muscular body for the maintenance
of good health. He has evidently worked at and thought a good deal
about this side of the subject.

He regrets that there are not more people who realise the huge
importance of understanding the nutrition problem for the sake of
the progress of humanity. He would like to join all those who are
interested in forming an international society, as far as I understood
him.

He is most keen on getting subjects, such as myself, for study over
a very long period of time,--two to three years,--as he very justly
observed “Muscular output is a very small part of the measure of a
man’s efficiency. Mental efficiency, manual dexterity, and other
psychological tests are necessary.” He seemed very much interested in
my idea of making a large number of curves of daily observations. He
said that it appeared to him to offer the best means of ultimately
measuring the degree of deviation from the subject’s optimum state of
health.

He argues the necessity of getting some scientific definition of health.

* * * * *

The phrase that reduces all these people to contemplative silence is
this.

“You acknowledge that the state of knowledge is insufficient to
prescribe a diet for any individual that he should take daily; or
in other words, that there is very little accurate knowledge of the
nutrition problem.”

Reply. “Yes. I do not feel I could prescribe a diet for any one with
any degree of confidence.”

“Very well, then. Why should not the body have or acquire the quality
that all animals have, in a free, natural state, of knowing what their
body wants by appetite and taste?”

This is more or less how you put it to me when I first met you at
Cambridge. Its full significance did not dawn on me till much later;
till, in short, I commenced the study of my desires at Cambridge.

Now this point of view is the rock on which we stand, and is the cause
of H.'s and A.'s interest, and as H. said, is the “most fascinating
idea” he ever heard.

It had very much the same effect on A. He was reduced to silence. The
more you think of it the more you see there is no answer that could
contradict it.

_He then admits that_

(_a_) The food should be finely divided.

(_b_) That it should be thoroughly insalivated.

(_c_) That in all probability most diseases are caused by dietetic
error.

(_d_) That we have still to find the optimum health and the optimum
diet.

He only kicks at the low proteid. Now I don’t care a “kuss” for the low
proteid, as such, or high proteid. Proteid like everything else will
be demanded by the appetite when it is wanted.

Our great danger, to my mind, is the tendency so strongly exemplified
by some of prescribing diets and quantities and the length of time food
should be chewed.[1] Now the very errors we are fighting against are
the prescription of methods on insufficient information or knowledge.
_You have gone straight back to Nature._ _There is your strength_ in
convincing the scientific world, and we must study the problem from
that point of view if we are to get any great degree of success.

A. had nothing to say when I told him that I did not hold by either
high or low proteid but only by my appetite and taste, developed by
ample mouth opportunity to discriminate, which I hoped, in time, to
understand more thoroughly than I do now. He told me that he feared
that there would be great physical deterioration after a long period
of low proteid. I said that I did not believe it would be the case by
your method. For instance, right in the midst of a long period of most
satisfactory low-proteid supply, I once ate nearly a whole chicken
with some ham at Penegal. I could not get saliva for anything else.[2]
In short, then, I insisted only on thorough mastication to protect
taste and appetite, and had no other theories. I was only concerned
in observing the factors determining my taste and appetite. I would
be more than contented to leave the question of minimum and maximum
quantity of proteid to be settled in the future after normality had
been established by practical demonstration.

Yours faithfully,
HUBERT HIGGINS.

EXTRACTS FROM DR. KELLOGG’S LETTER

BATTLE CREEK, MICH.
October 7, 1903.
MR. HORACE FLETCHER.

DEAR FRIEND,--Yours of September 30th just reached my hands and I
hasten to reply.

I saw a newspaper note in reference to the soldiers which the
government has selected for the dietetic experiments, and also read
an interesting article in the _Popular Science Monthly_. You have
accomplished a great good thing in enlisting these scientific and
military men and interesting them in the investigation of this
wonderful reform. The marvellous thing about it is that these busy men
of science should have so readily undertaken an investigation which
involves so much surrender and self-denial, at least, at the start. I
know you are absolutely right. My personal experiences and observations
confirm me. In the experiments you mention, which I made in reference
to the daily ration for ordinary persons, I simply sought to ascertain,
as have others, how much and what kinds of food people are in the habit
of using, taking no account of the possible excess or the careless
manner in which they eat. The figures I got were sixteen ounces of
starch; 1.2 ounces fat, and three ounces proteids,--approximately 2,500
calories. In observation of patients I have seldom found one able to
eat this amount. Personally, I habitually eat scarcely half as much. My
breakfast to-day was the yolks of two eggs, two or three tablespoonfuls
of corn flakes, a moderate-sized potato, and a couple of peaches. At
dinner I shall take a little more.

I have been so busy with my patients and the new building, getting
things organised, that I have not done as much as I ought to in the
way of promoting your splendid reform; but I am going at it now in
good earnest. I feel it is one of the greatest things in sight, and it
fits right in to all the other things I am trying to do. I feel that
I owe you continually a great debt for the efforts you have made and
the splendid work you are doing, which will accomplish more for the
uplifting of humanity than all that Carnegie and Rockefeller are doing
with their millions. What they are doing is mainly to perpetuate old
errors, while you are bringing out new truth of basic importance, and a
kind Providence has certainly inspired you to do this grand work.

I thank you for all your good thoughts towards us, and assure you
the loving encouragement your letters always contain is very much
appreciated, and sometimes it gives us a mental uplift just when we
need it. The road we are travelling over is not altogether free from
thorns. All your suggestions are gratefully received. I remain,

Faithfully yours,

J. H. KELLOGG.

A. B.-Z. PRIMER

EXPLANATION

This is a condensed presentment of a subject of basic importance to
everyone, supported by numerous appendices of great scientific weight.

The special object of such brevity and elementary treatment of the
subject is:

=1.= To accentuate the facts showing how little we really have to know
and do in connection with our sustenance in order to have the NATURAL
AUTOMATIC PROCESSES done rightly and healthfully.

=2.= To permit busy persons who will take our dictum as gospel and our
advice as sound to learn their necessary share in their own nutrition
in the least possible time, leaving the less credulous and more curious
to study the appendices at leisure and at will.

=3.= For some ten years it has been the ambition and the aim of the
older and non-professional author to embody the fundamental essentials
of human responsibility in self-understanding and self-management in
not more than ten pages of coarse print that a child could understand
and that mothers and teachers might commit to memory and never forget.

This is only a first trial-attempt to fulfil the ambition and the aim;
but the appendices show the assembling and concentration of scientific
and militant forces which will not allow this subject of primal
human interest to remain longer the most neglected of educational
departments.

SOME PERTINENT QUESTIONS

Will the reader not ask himself the following questions?

=1.= How much do I know about my own nutrition?

=2.= Do I know the particular need and purpose of my last meal and what
it is likely to accomplish?

=3.= Considering my body as an engine, would I accept myself as a
competent engineer on my own examination and confession?

=4.= Were I an iron and steel automobile, instead of a flesh and blood
automobile, which I really am, could I get a license for myself, as a
_chauffeur_, to run myself with safety, based upon my knowledge of my
own mechanism and the theory and development of my power?

=5.= Were I an owner of valuable live-stock, would I employ a farm-hand
or a stable man, even at so low a wage as fifteen dollars a month, who
knew as little about the proper feeding of my animals as I know about
the proper feeding of myself and my children?

=6.= Should I employ such an ignorant attendant for my live-stock, and
catch him worrying them during their feeding, and hurrying them away
from their fodder to hitch them up for work, would I not have the man
arrested for cruelty to animals? And yet this is what is habitually
done to children!

=7.= Do I appreciate how important it is to learn sufficient of the
requirements of economic and healthy nutrition to enable me to escape
the depressing and debilitating effects of a faulty nutrition.

=8.= How can I religiously “ask a blessing” upon food and then
immediately sin by treating it in a manner abhorrent to the natural
requirements?

=9.= If “cleanliness is next to godliness” is it respectable for me to
slight my proper feeding in a manner that I know may induce putridity
of excreta through indigestion and that _may_ produce fatal disease?

=10.= With All Eternity ahead of me, cannot I afford at least 1∕48[3]
of my time for careful feeding of my body in a manner known to favour
physical health; mental keenness; firmness of character; enjoyable
temperance; sexual vigour without morbidity. In fact, general
respectability and efficiency?

Having duly reasoned out logical answers to the questions, may they not
seem sufficiently important to be remembered and respected as a DIETARY
TEN COMMANDMENTS?

The Psychology of Nutrition

APPETITE ATTENTION APPRECIATION

APPETITE is the most important factor in digestion (vide Pawlow).

NORMAL APPETITE is indicated by a desire for _some particular_ simple
food accompanied by a “watering of the mouth.”

FALSE APPETITE is a general discontent of the body, indefinite of
description. It is often expressed by “all gone-ness,” or stomach
craving, and calls for _something_, ANYTHING! to smother the discomfort
of present or recent indigestion. It is like the thirst which follows a
debauch.

IGNORE FALSE APPETITE, and WAIT for a RETURN of NORMAL APPETITE.
It will come as soon as body repairs have been effected by natural
agencies and more material is required. No one was ever injured by
intelligently and calmly waiting for an appetite. No one ever starved
to death for lack of appetite. Most human ills come from forcing
appetite, anticipating appetite, abuse of appetite in some form.

APPETITE is the most important factor in nutrition. This estimation is
based upon evidence given more fully in the various appendices, but the
measure of its importance may be briefly stated, as follows:—

_First_

In its normal state, Appetite is a perfect indicator of the bodily need
of nutriment and moisture, both as to quantity and as to the chemical
elements required at the moment.

_Second_

APPETITE is a creature of the mind and does not attach to a tissue.
It can be as easily changed, from abnormal to normal, by suggestion,
as can the mind itself, and is not like a solid, the form or habit
of which has been set in a mould. Whoever has once experienced a bad
oyster and has abhorred oysters ever after will substantiate this claim
regarding the caprices of appetite.

_Third_

APPETITE can be easily comprehended and read and the degrees of its
satisfaction understood by simple attention and study for a brief
period (vide Van Someren).

_Fourth_

ATTENTION is necessary to create APPRECIATION, and appreciation is
absolutely necessary to stimulate the secretion and flow of gastric and
other digestive juices (vide Pawlow).

_Fifth_

ANGER, or shock of any kind, and WORRY, or any of the pessimistic
depressants, stop digestive activity and cause indigestion (vide
Cannon).

_Sixth_

MENTICULTURE should begin with its application to selection (through
a normalised appetite) of nutriment for the body, and continue to aid
digestion by right thinking.

It is very easy to cultivate calm and fortify against surprise, shock,
and anger if the nutrition of the body is carefully attended to. The
physical and the mental equipments are beautifully reciprocal and
necessary to each other in promoting MENTICULTURE.

The Mechanical and Chemical Physiology of Nutrition

BUCCAL DIGESTION

THROUGH

MOUTH THOROUGHNESS

Mouth treatment of food, which permits, aids, and includes insalivation
(mixing with saliva), and which is both actively digestive in its
functions and preparatory to final digestion, is the only _actual
mechanical responsibility_ we have in our nutrition; and, in connection
with favourable A conditions, insures perfect digestion. It has been
so fully and clearly explained in some recent articles, “Observations
on Mastication,” by Dr. Harry Campbell, F.R.C.P., physician to the
Northwest London Hospital, printed in the “Lancet” of July 11th, 18th,
25th, and August 8th, 1903, that reference to the articles, reprinted
herewith, is all that is necessary here.

In giving attention to careful mouth-treatment of soft or liquid foods
until they are absorbed by the Swallowing Impulse the best health and
economic results are obtained. It should, at least, be tried.

This will not be found to be a tedious operation after a little
practice, when the habit of attention and care has been formed. On the
contrary, a new appreciation and enjoyment of taste will be acquired,
the delight of which has to be experienced to be understood.

Some hints on learning how to _read_ the appetite, _command_ the
attention, and _masticate_ and _swallow_ food material _properly_
follow.

METHOD

_First; Last; and All the Time_

Be sure that you are really hungry and are not pampering False
Appetite. If true appetite that will relish plain bread alone is
not present, wait for it. Especially beware of the early-morning
habit-craving. Wait for an _earned_ appetite, if you have to wait till
noon. Then: “Chew,” “Masticate,” “Munch,” “Bite,” “Taste” everything
you take in your mouth (except water, _which has no taste_), until
it is not only thoroughly liquefied and made neutral or alkaline
by saliva, but until the reduced substance all settles back in the
(glosso-epiglottidean) folds at the back of the mouth and excites
the Swallowing Impulse into a strong inclination to swallow. Then
swallow what has collected and has excited the impulse, and continue
to chew _at_ the remainder, liquid though it be, until the last morsel
disappears in response to the Swallowing Impulse. Never forcibly
swallow anything that the instincts connected with the mouth show any
disposition to reject. It is safer to get rid of it beforehand than to
risk putting it into the stomach.

Sip and taste milk and all liquids that have taste as the wine-tasters
do. They never drink wine and yet they get all the enjoyment there is
in it and waste none. In a very short time sipping and tasting liquids
and masticating and tasting solid food for “all they are worth” will
become an agreeable and profitable fixed habit.

WHETHER WE “EAT TO LIVE OR LIVE TO EAT,” WHY NOT DO AS ABOVE?

The True Chemical End-Point of Digestion

THE DIGESTION-ASH WHAT IT SHOULD BE LIKE WHEN IT IS NORMAL

_First_

In adults; or, in children after the eruption of teeth and the
ingestion of solid food: The non-liquid and non-gaseous waste of the
human body, which, in its normal state, is not offensive, should be
very small, in quantity, should be pillular in form, either separate or
massed together; should have no odour when released, should take on no
odour on standing, should be entirely aseptic (non-poisonous); should
drop freely from the exit, leaving nothing behind to wash or wipe away.
It _may_ not be collected in the intestines of full-grown and elderly
persons, when normal, as above, in sufficient quantity to require or
necessitate emptying oftener than from twice a week to once in two
weeks; according to age, activity, etc.; and should neither invite nor
justify the description “it is not that which goeth into a man that
defileth him but that which cometh out.”

_Second_

Economic Digestion-Ash (solid _excreta_), as a daily average for an
adult of 140 lbs. (10 stone; 63.5 kilos), including moisture, when
released, should not weigh more than two ounces (56.70 grams). An
average of less than one half this amount of waste has been secured in
test experiments.

_Third_

The true test of healthy Z is absence of odour and completeness, ease
and cleanliness of delivery. Frequency or otherwise, does not so much
matter. Quantity too, is not so important; but with foul odour there is
disturbance, strain and danger.

The normal man is a cleanly being with all excreta inoffensive; and by
these tokens he may be his own private judge.

Why is it that barn-yards are tolerable to the human senses while open
_dépôts_ of human excreta are fever-breeding nuisances and intolerable
to beasts and humans alike?

This curse of putrid excreta caused more deaths from enteric fever
during the Boer War in South Africa than all other causes. It is
equally a menace to health and even to life while being formed and
carried in the body.

_Fourth_

Offensive excreta are quite certain evidence of neglect of the
self-controllable parts of our own nutrition. They are the tell-tale
condemnation of ignorance or carelessness. Each person should learn to
read the true bulletins of his health conditions in his waste-products
of digestion.

is the form the body _must_ assume to render emptying of the
digestion-ash natural and easy. Man was built to squat on his heels in
defecating, and sitting erect on a modern seat is like trying to force
a semi-solid through a kinked hose. HEALTHY HUMAN EXCRETA ARE NO MORE
OFFENSIVE THAN MOIST CLAY AND HAVE NO MORE ODOUR THAN A HOT BISCUIT.

A. B.-Z. FIGURE

TO ILLUSTRATE THE “DIVISION OF LABOUR”

_First._ A

Psychic Environment } This
Mental State } involves:

APPETITE (to select for) }
ATTENTION (to prepare for) } DIGESTION
APPRECIATION (to assist in) }

(Absolutely necessary to secure secretion and flow of the digestive
juices: Vide Pawlow and Cannon.)

_Second._ B

BUCCAL-DIGESTION } This
MOUTH-TREATMENT } involves:

MECHANICAL (teeth) } THOROUGHNESS
CHEMICAL (salival) }

(Absolutely necessary to secure complete digestion and avoid the
putridity incident to bacterial decomposition: Vide Campbell and Van
Someren.)

INTERMEDIATE

The twenty-three letters between “=B=” and “=Z=” represent but an
inadequate proportion for the spelling of the enormous share Nature
assumes in our welfare, marvellously performing her forty-seven
forty-eighths share in the secret laboratory of the alimentary canal.

_Third._ Z

The true chemical end-point of digestion, by which each self-respecter
may know how well he has respected his “A” and his “B,” and how
faithfully he has performed his one forty-eighth share in the promotion
of his own most fundamental interest.

PREFACE TO 1906 EDITIONS

Since the former introductions were written much success has been
attained in further advancing the reforms advocated in the _A. B. C.
Life Series_. Professor Chittenden has published his report on the
Yale experiments in book form in both America[4] and England,[5] and
his results have been accepted in scientific circles the world over as
authoritatively conclusive.

At the present writing the most important Health Boards of Europe[6]
are planning to put the new standards of dietary economy into practical
use among public charges in a manner that can only result in benefit
to the wards of the nations as well as make an important saving to
the tax-payers. In the most important of these foreign public health
departments the Health Officer of the Board has himself practised the
newly established economy for two years, and his plans are formulated
on personal experience which fully confirms Professor Chittenden’s
report and that of the author as herein related.

At a missionary agricultural college, situated near Nashville, Tenn.,
where the students earn their tuition and their board while pursuing
their studies, a six months' test of what is termed “Fletcherism”
resulted in a saving of about one half of the drafts on the commissary,
immunity from illness, increased energy, strength and endurance, and
general adoption of the suggestions published in the several books of
the author included in the _A. B. C. Life Series_.

In the various departments and branches of the Battle Creek Sanitarium
in America, and widely scattered over the world, some eight hundred
employees and thousands of patients have been accumulating evidence of
the efficacy of “Fletcherism” for more than three years, and scarce a
month passes without a letter from Dr. Kellogg to the author containing
new testimony confirming the _A. B. C._ selections and suggestions.

The author has received within the past two years more than a thousand
letters bearing the approval of the writers with report of benefits
received which seem almost miraculous, and these include the leaders in
many branches of human occupation--physiologists, surgeons, medical
practitioners, artists, business men, literary workers, athletes,
working men and women, and almost every degree of mental and physical
activity.

One of the medical advisers of King Edward, of whom the King once said:
“He is a splendid doctor but a poor courtier,” follows the suggestions
of these books in prescribing to his sumptuous clients.

HISTORY OF DEVELOPMENT

AND

SUPPORTING EVIDENCE

SUMMARY OF THE FOREGOING PAGES BY AN EXPERIMENTER OF ONE MONTH’S
EXPERIENCE

(_Requested and given as a test of effectiveness_)

The entire principle of economic nutrition is simple and practical. It
does not prescribe that we shall follow any special diet nor do away
with any of our meals. It simply requires you to throw present habits
and conventions to the winds, and for a little time try the experiment
of giving the matter of your every-day living honest, intelligent
thought.

Eat all you crave, but do not eat more than this simply because you
have been in the habit of doing so. See to it that each morsel put into
your mouth is thoroughly masticated and mixed with the saliva before
going down into the stomach, which is not equipped to perform the work
which the teeth and salivary glands were given you for. The stomach
will struggle bravely to overcome the abuse which you heap upon it, but
in spite of all it can do to manage hastily chewed food, undigested
portions remain which clog the intestines and interfere with the
healthy conditions which Nature intended.

The appetite is given as an indicator of what the body requires. If
you crave potato, the system needs starch, which the saliva makes
digestible, but which the acids of the stomach cannot dissolve. Other
needs of the system are similarly indicated. Take the trouble of asking
your appetite the question, instead of accepting the conventional
number of courses simply because they are set before you. The appetite
will close the valve when you have eaten enough, if you will give it a
chance.

Suppose your time for eating is limited; in twenty minutes you could
not eat slowly the luncheon which you usually select. Then eat that
much less. The amount of food which you can eat and thoroughly
masticate in twenty minutes will give you more nourishment and will
sustain you better than twice the amount thrown into the stomach in the
same manner in which a man usually packs a trunk.

Why is it that so many men require a “bracer” at eleven o’clock?
Because they have loaded their stomachs with a heavy breakfast, and
instead of gaining nourishment from it, the smothered organ is doing
its best to tear the undigested morsels to pieces, that they may pass
into the intestines and prevent sickness, or even death. The time
finally arrives when it finds itself unable to do this, and then comes
acute indigestion, or something worse, and the system becomes run down,
ready to receive typhoid, or any other germs which happen to come along.

Do you know why griddle-cakes hurt you? Because the syrup, which is
cane-sugar,--and as such is indigestible,--is allowed to pass through
the mouth and down into the stomach, without being properly mixed with
the saliva, which makes it digestible. As soon as it enters the stomach
it becomes acid and interferes with everything it meets. Had the cakes
been properly masticated and mixed with the saliva, the cane-sugar
would have become grape-sugar, and in this form it is easily digested.

Why is it that stout people are advised to avoid starchy foods?
Economic nutrition does not advise this. Potatoes, eaten too
hastily, when not craved by the appetite, supply the system with a
superabundance of starch, and this is fat-inducing. Potatoes are
supposed to produce fat; but if your appetite craves potato, and you
properly masticate it, eating only as much of it as satisfies your
appetite, the system absorbs it all, leaving nothing to produce fat.
On this same principle economic nutrition assures that the same food,
taken in accordance with its requirements, will add to one man’s
weight and decrease another’s, simply because proper care of the
stomach supplies the vital organs with the necessary materials to form
each individual person after the model which Nature intended for him.
If Nature intended him to be slight, economic nutrition will not make
him heavy; if Nature intended him to be muscularly strong and heavy,
economic nutrition will not reduce his weight. In each case he will
enjoy that perfect condition which Nature intended him to possess
without fat encumbrance.

Did you ever try to reason out why it is necessary for athletes to go
into training? Simply because, in order to get the best use of their
strength, they are obliged to spend some number of weeks or months in
overcoming false conditions which they have brought upon themselves.
Any person who lives in accordance with the simple requirements of
economic nutrition has nothing of this kind to overcome, but is in
perfect condition all the time.

The requirements of economic nutrition are not hardships but pleasures.
Proper mastication and insalivation (mixing with saliva), give your
sense of taste far greater gastronomic enjoyment than you have ever
before had. If you are a wine drinker, try insalivating a little port
wine; but it must be good wine, for this is a severe test. A sip will
quench your immediate desire and give you more pleasure than a whole
glass gulped down. The professional tea-taster does this in tasting
tea; he never allows himself to drink any tea at all, for drinking
anything that has taste destroys the delicacy of the sense of taste.
But he will tell you that he gets more real enjoyment out of the little
he takes than he previously gained from drinking a larger amount. The
same thing applies to the professional wine-tasters; they never drink
any wine, and yet they enjoy the taste of wine as drinkers never can
do. These men adopt this method as a business; is their commercial
advantage of greater importance than your health and happiness, and
even life itself?

Is it not ridiculous that the average man is so ignorant of the engine
which supplies him with all his activity and upon which depends every
action of his life? Could you tell, were you asked, the particular need
and purpose of your last meal and what it is likely to accomplish?
Consider your body as an engine: would you accept yourself as a
competent engineer on your own examination and confession? Would you
employ a chauffeur to run your automobile who knew as little about its
mechanism and requirements as you do about your own stomach? Yet which
is of greater importance? Were you the owner of valuable live-stock,
would you dare entrust their care to a farm-hand or stableman who knew
as little about their proper feeding as you know about your own proper
feeding or that of your children?

Have you ever stopped to think why the excrements are foul and odorous?
Simply because undigested food, which should have been so masticated
as to give the body nourishment, is thrown off by the stomach into the
intestines, there to decay and produce this unclean condition. If the
dead carcass of a cow is lying in the road, it is removed before it has
an opportunity to decay and thus become filthy and dangerous. Yet how
much more safe it would be for the carcass to lie where it was than
for you to take portions of it into your intestines and allow it to
decay there instead of in the road? In other words, food is intended
to be eaten that nourishment may be gained from it, and when you only
gain a part of the nourishment, you prostitute your stomach and take
tremendous risks of germ diseases in your body.

These facts are set forward thus simply in the hope that they may
impress the reader as they have impressed the writer. Economic
nutrition is not a joke, is not a fad; it is solely an appeal to
self-examination and self-instruction in the most vital question of
all the world, since upon perfect nutrition depends not only health,
but strength, mental acuteness, moral tendencies, attractability to
others, happiness, and, in fact, life itself.

FIRST SCIENTIFIC RECOGNITION OF THE PRINCIPLES OF ECONOMIC NUTRITION
OUTLINED IN “GLUTTON OR EPICURE”

[With the exception of a brief review of _Glutton or Epicure_, by Dr.
Joseph Blumfield, of London, published in _The Lancet_, no scientific
or professional recognition of the principles of an economic nutrition
attained by means of thorough buccal digestion was gained until issue
of the following paper by Dr. Ernest Van Someren, of Venice, Italy.

The previous autumn and winter had been devoted to experiments by
Dr. Van Someren and the writer, in co-operation with Dr. Professor
Leonardi, for twelve years Professor of Chemistry in the University of
Pavia, Italy. In the spring and summer of 1901 the field of experiments
was changed to Mendel Pass, _bei_ Bozen, Süd Tirol, Austria, and
related to endurance work in climbing mountains and bicycle runs among
the Dolomites.

Dr. Van Someren’s paper attracted the attention of Sir Michael Foster,
Professor of Physiology at the University of Cambridge, England,
and Permanent Honorary President of the International Congress of
Physiologists.

Professor Foster entered into correspondence with Dr. Van Someren, and
this was followed by an invitation to Dr. Van Someren and the writer to
attend the Congress which was to convene in Turin, Italy, during the
month of September following. At the Congress Dr. Van Someren presented
a technical thesis on the probable causes of the economy attained,
and gave a demonstration of the movement of his Swallowing Reflex
in relation to food in the process of liquefaction and preliminary
digestion in the mouth.

Following the Congress we received an invitation to visit Cambridge,
England, and submit to tests of nitrogenous measurements in the
Physiological Laboratory of the University, under the direction of Dr.
F. Gowland Hopkins; and also to an examination of the bacterial flora
incident to the nitrogenous estimations, under the direction of Dr.
George H. F. Nuttall.

The report of the experiments in the Chemical-Physiological Department
is given in the “NOTE” of Sir Michael Foster, which follows Dr.
Van Someren’s paper, but the bacterial examination was not carried
far enough to warrant a scientific report, owing to difficulty of
obtaining, at the time, sufficient data.—HORACE FLETCHER.]

WAS LUIGI CORNARO RIGHT?

A PAPER READ BEFORE THE PHYSIOLOGICAL SECTION OF THE BRITISH MEDICAL
ASSOCIATION, AUGUST, 1901, BY ERNEST VAN SOMEREN

_Mr. President and Gentlemen:_

Being a general practitioner, it is with some trepidation and an
apology that I present myself before this section. The reasons for my
doing so are: First, that I believe that a hitherto unsuspected reflex
in deglutition has come to light which has an important bearing on
health, the prevention of disease and on metabolism. Second, that any
theory whatever, based on a possible physiological function, claiming
to diminish, as this does, the amount of sickness and suffering now
existent, should have serious investigation. Third, that I desire to
enlist your skilled help in the consideration of the theories I have
doubtless crudely erected on my premise.

According to the “Encyclopædia Britannica,” “Luigi Cornaro (1467-1566)
was a Venetian nobleman, famous for his treatises on a temperate life.
From some dishonesty on the part of his relatives, he was deprived
of his rank and induced to retire to Padua, where he acquired the
experience in regard to food and regimen which he has detailed in his
work. In his youth he lived freely, but after a severe illness at
the age of forty, he began under medical advice gradually to reduce
his diet. For some time he restricted himself to a daily allowance
of 12 ozs. of solid food and 14 ozs. of wine. Later in life he still
farther reduced his bill of fare, and he found that he could support
his life and strength with no more solid meat than an egg a day. So
much habituated did he become to this simple diet that when he was
about seventy years of age the addition, by way of experiment, of 2
ozs. a day had nearly proved fatal. At the age of eighty-three he
wrote his treatise on the ‘Sure and Certain Method of Attaining a
Long and Healthful Life.’ And this work was followed by three others
on the same subject, composed at the ages of eighty-six, ninety-one,
and ninety-five, respectively. ‘They are written,’ says Addison
(‘Spectator,’ No. 195), ‘with such a spirit of cheerfulness, religion,
and good sense, as are the natural concomitants of temperance and
sobriety.’ He died at the age of ninety-eight. Some say of 103!

Now, was Luigi Cornaro right? Did he make use of a physiological
process unknown to us of the value of which he was not cognisant? To
live to an advanced age, must we be as temperate as he, reducing the
quantity of our food to a minimum required by Nature?

That we all eat more than we can assimilate is unquestionable. How can
we determine the right quantity? Instinct _should_ guide us, but an
abnormal appetite often leads us astray. Nature’s plans are perfect
if her laws are obeyed. Disease follows disobedience. Wherein do we
disobey?

We live _not_ upon what we eat, but upon what we digest; then why
should undigested food, recognisable as such, be deemed a normal
constituent of our solid egesta?

Something like the following must be a common experience to general
practitioners, especially to those practising on the Continent. The
patient comes to see us and volunteers the information that he or she
has the “gout,” “rheumatic gout,” or “dyspepsia.” Symptoms are asked
for. The case is gone into carefully for causation. An appropriate
diet and an appropriate bottle of medicine prescribed. As the patient
leaves the room, we may, or may not, call attention to the fact that
both teeth and saliva are meant to be used. The patient returns,
better, _in statu quo_, or worse. If better, he remains so while
under treatment, and relapses when he returns to ordinary habits. If
unaffected, or worse, we try again and again, until we despair, then
take or send him to a consultant. Temporary benefit, possibly owing to
renewed hope, results; but finally the unfortunate gets used to his
sufferings and, if he can afford it, is sent to join the innumerable
hosts that wander from one _Bad_ to another, all Europe over, trying,
praising, and damning each in turn. Their manner of living is, of
course, at fault. Nature never intended that man should be perpetually
on a special diet and hugging a bottle of medicine, nor did she ordain
that he should go wandering over the map of Europe drinking purgative
and other waters.

Though early yet to speak with certain voice, it would seem that we
are provided with a Guard, reliance on which protects us from the
results of mal-nutrition. There seems to be placed in the fauces and
the back of the mouth a Monitor to warn us what we ought to swallow and
when we ought to swallow it. The good offices of this Monitor we have
suppressed by habits of too rapid eating, acquired in infancy or youth.

Last November my attention was called by Mr. Horace Fletcher, an
American author living in Venice, to the discovery in himself of a
curious inability to swallow, and a closing of the throat against food,
unless it had been completely masticated. My informant stated that he
noticed this peculiarity after he had begun to excessively insalivate
his food, both liquid and solid, until all its original taste had been
removed from it. Any tasteless residue in the mouth, being refused by
the fauces, required a _forced_ muscular effort to swallow. He further
told me that since adopting this method of eating he had been cured of
two maladies, adjudged chronic, the suffering from which rendered him
ineligible for Life Insurance. His weight now became reduced from 205
lbs. to 165 lbs. He had practised no abstemiousness, had indulged his
appetite, both as to selection and to quantity, without restraint, and
for the last three years had enjoyed perfect health.

After his cure, he was accepted without difficulty for insurance, the
last examination finding him an unusually healthy subject for his age.
Having leisure, he had spent three years in investigating the cause of
his cure, had pursued experiments upon others, and had extended his
inquiries, both in America and Europe, until our meeting in Venice.
He had also published a statement and inquiry in book form, entitled
“Glutton or Epicure,” which had been reviewed by the “Lancet.”

For nearly a year I also had been experimenting on myself and others
with various diets, and was ready to believe that in the _manner_ of
taking food and not altogether in its varying _matter_ lay perhaps its
protean effects on our system. I at once adopted the same method of
eating. At the end of six weeks, I noticed that not only did the fauces
refuse to allow of the passage of imperfectly prepared food, but that
such food was returned from the back to the front of the mouth by an
involuntary, though eventually controllable, muscular effort taking
place in the reverse direction to that occurring at the inception of
deglutition.

What actually happens is this: Food, as it is masticated, slowly passes
to the back of the mouth, and collects in the glosso-epiglottidean
folds, where it remains in contact with the mucous membrane containing
the sensory end-organs of taste. If it be properly reduced by the
saliva it is allowed to pass the fauces,--a truly involuntary act of
deglutition occurring. Let the food, however, be too rapidly passed
back to these folds, _i.e._, before complete reduction takes place,
and the reflex muscular movement above referred to occurs. The process
of this reflex is as follows: The tip of the tongue is involuntarily
fixed at the backs and bases of the lower central incisor teeth by the
anterior fibres of the geniohyoglossi muscles. With this fixed point
as fulcrum, the lower and middle fibres of these muscles, aided by
those of the stylohyoid and styloglossi muscles raise the hyoid bone,
straighten out the glosso-epiglottidean folds, passing their contents
forward, by the fauces, the opening of which is closed by approximation
of its pillars and contraction of the superior constrictor. The
tongue, arched postero-anteriorly by the geniohyoglossi, palato, and
styloglossi muscles, laterally, by its own intrinsic muscles, is
approximated to the fauces, soft and hard palates in turn, and thus,
the late contents of the glosso-epiglottidean folds are returned to the
front of the mouth for further reduction by the saliva preparatory to
deglutition.

The word reduction is used for the reason that all foods tested,
without exception, give an acid reaction to litmus, when served at
table. The reflex muscular movement occurs in the writer’s case from
five to ten times during the mastication of each mouthful of food,
according to its quantity and its degree of sapidity. As often as it
recurs, the returned food continues to give an acid reaction, while
food allowed to pass the fauces is alkaline.

Saliva, flowing in response to the stimulation of taste, seems more
alkaline than that secreted in answer to mechanical tasteless
stimulation. It is found that the removal of original taste from any
given bolus of food coincides with cessation of salivary flow and
complete alkaline reduction. The fibre of meat, gristle, connective
tissue, the husk of coarse bread and cellulose of vegetables are
carefully separated by the tongue and buccal muscles and rejected by
the fauces. To swallow any of these necessitates a _forced_ muscular
effort, which is abnormal.

Adult man was not originally intended to take his nourishment in a
liquid form, consequently all liquids having taste, such as soup, milk,
tea, coffee, cocoa, and the various forms of alcohol, must be treated
as sapid solids and insalivated by holding them in the mouth, moving
the tongue gently, with straight up and down masticatory movements,
until their taste be removed. Water, not having taste, needs no
insalivation and is readily accepted by the fauces.

In explanation of the phenomenon described, the following theory is
advanced: The fauces, back of the tongue, epiglottis, in short, those
mucous surfaces in which are placed the sensory end-organs of taste
and “taste-buds” (the distribution of which, by the way, has yet to
be explained), that these surfaces, readily becoming accustomed to
an alkaline contact by excessive insalivation and consequent complete
alkaline reduction of the food, afterwards resent an acid contact and
express their resentment by throwing off the cause of offence by the
muscles underlying them.

This phenomenon must not be confused with the cases of rumination and
regurgitation, which from time to time are recorded. The food in this
case is not swallowed, nor does it pass any point from which it can
be regurgitated. Eighty-one individuals of different nationalities
and from several classes of society whom we have studied are now in
conscious possession of their reflexes. These seem readily educated
back to normal functions by all who seriously and patiently adopt the
habit of what seems only at first to be excessive insalivation.

The dictum “bite your food well” that we so often use, has no
meaning to those suffering from the results of mal-assimilation and
mal-nutrition, especially should they have few or no teeth of their
own. I make so bold as to state that dyspepsia _et morbi hujus generis
omnis_ will cease to exist if patients be persuaded to bite their
food until its original taste disappears, and it is carried away by
involuntary deglutition.

The important point of the whole question seems to be this alkaline
reduction of acid food before it passes on to meet subsequent
digestive processes elsewhere, which then become alternately acid and
alkaline.

In the first few months of infant life, when saliva is not secreted,
Nature ordains that mammary secretion be alkaline. With the eruption
of teeth come an abundant flow of saliva and a synchronous infantile
capacity for managing other foods. This flow of saliva depends on a
thorough demand and use to maintain its generous supply. It is just
at this time that children learn to bolt their food,--the demand
fails, with a consequent detriment to the salivary glands, digestive
processes, and the system generally.

A, B, C, and D were placed on an absolute milk diet. A drank his milk
in the ordinary way, and at the end of three days begged to discontinue
the experiment owing to disgust at the monotony of the diet. B, C, and
D continued the experiment for seventeen days, insalivating the milk,
but to a varying extent, B the least and D the most. Though D took most
milk, he excreted least solid egesta, C excreting less than B. Can one
infer that increased insalivation of a non-starchy food insured its
better digestion and assimilation? Each subject took as much milk only
as his appetite demanded, D taking the most, which never exceeded two
litres daily. The weights of the subjects after the usual sudden drop
of the first three days remained remarkably even until the end of the
experiment. B, C, and D all relished the diet, and it satisfied the
requirements of their appetites, but they experienced an increasing
monotony.

As long ago as the seventeenth century, before the transformation of
matter into energy by the animal organism, known as Metabolism, was
understood, the fact was recognised that by the lungs, kidneys, skin,
and intestines, substances no longer useful to the organism were
eliminated, the retention of which proved harmful. The nature of these
substances was unknown, but it was noted that however much the food was
increased the weight of the body remained the same. In other words, a
state of complete nutritive equilibrium was maintained.

The following table contains the _résumé_ of two experiments in which a
state of complete nutritive equilibrium was maintained by individuals
of about the same weight, on widely different quantities of food
similar in quality. The subjects of the experiments were a laboratory
assistant of Dr. Snyder, of the U. S. Department of Agriculture, and
the writer. The experiment of the former was made primarily to show
the relative digestibility of the several articles of diet, potatoes,
eggs, milk, and cream:

═════════════════════════╤══════════════════════════╤═══════════════
│ Dr. Snyder’s │
│ Experiment. │ Writer’s
│ Published in │ Experiment.
│ Bulletin 43 │
—————————————————————————┼————─—─—─—─—─—────—─—─—─—─┼─—─—─—───—─—─—─
Age of subject │ 22 years │ 30 years
Duration of experiment │ 4⅓ days │ 5 days
Number of meals │ 13 │ 10
Weight at beginning │ 62.5 kilos. │ 57.3 kilos.
Weight at end │ 62.6 kilos. │ 57.5 kilos.
Potatoes (daily average) │ 1587.6 grammes │ 159.4 grammes
Eggs (daily average) │ 411.08 grammes │ 124.7 grammes
Milk (daily average) │ 710 c.c. │ 710 c.c.
Cream (daily average) │ 237 c.c. │ 237 c.c.
Daily urine │ 1108 grammes │ 1098 grammes
Daily fæces │ 204 grammes │ 18.9 grammes
—————————————————————————┴————─—─—─—─—─—────—─—─—─—─┴─—─—─—───—─—─—─

The daily diet of Dr. Snyder’s subject consisted of three and one-half
pounds of potatoes, eight eggs, a pint and a half of milk, and half a
pint of cream. The writer’s diet of twelve ounces of solid food (like
Luigi Cornaro) consisted of three eggs, the remainder of the twelve
ounces in potatoes, and an equal quantity of similar liquid food to
that taken by Dr. Snyder’s subject. The exercise of the laboratory
assistant comprised his daily routine of laboratory work, while that of
the writer consisted of six sets of tennis, or an hour and a half on
horseback, with an hour to an hour and a half’s walk or climb daily, in
addition to much reading and writing.

In each case complete nutritive equilibrium was maintained, although
the author subsisted on three-seventeenths of the solid food taken by
the other subject.

Again, cannot one infer that better assimilation and less waste
resulted from the better preparation of the smaller quantity of food
by insalivation? Surely, too, there must be less daily strain on the
intestinal canal, and body generally, in getting rid of 18.9 grammes
of inoffensive dry waste, than in getting rid of 204 grammes of humid,
decomposing, and offensive matter.

“Considerable importance has been attached to the normal action of the
bacteria in the intestines; and it has even been supposed that the
presence of bacteria is essential to life. Such a view has recently
been shown to be erroneous by an elaborate and painstaking research
carried out by Nuttall and Thierfelder, who obtained ripe foetal
guinea-pigs by means of Caesarean section carried out under strict
antiseptic precautions. They introduced the animals immediately into an
aseptic chamber through which a current of filtered air was aspirated,
and fed them hourly on sterilised milk day and night for over eight
days.

“The animals lived, and throve, and increased as much in weight as
healthy normal animals subjected to a similar diet for the purpose of
controlling the results. Microscopic examination at the end of the
experiment showed that the alimentary canal contained no bacteria of
any kind, nor could cultures of any kind be obtained from it.

“The same authors, in a subsequent paper, described the extension of
their research to vegetable food. This was also digested in the absence
of bacteria. Under such conditions cellulose was not attacked. Hence
they consider that the chief function of this material is to give bulk
and proper consistency to the food so as to suit the conditions of
herbivorous digestion.” (Schäfer’s “Text-Book of Physiology,” vol i. p.
465.)

Now, inasmuch as bacterial digestion has no place in the animal
economy, surely it can only occur at the expense of the organism?

Can micro-organic action take place in the intestines without the
production of toxins and the consequent absorption of these toxins into
the blood?

We know that the metabolism of a cell is determined by the general
physical environment of the whole organism, by supplies of oxygen and
water, on nervous impulses, and, what chiefly concerns this argument,
on the nature and amount of the pabulum supplied to it. This pabulum is
derived from the alimentary canal.

Are not even those of us who may be enjoying seemingly the best of
health supplying to our tissues pabulum containing mild toxins, thus
causing an increased katabolic action to occur in each individual cell
of our bodies?

Are not the blood elements, floating in a plasma containing such
toxins, rendered resistant, weaker, less capable of fulfilling their
functions as carriers and combatants of disease?

Are not their and our lives, in consequence, more painful and shorter
than they need be?

Would not the elimination of these toxins render us less liable
to disease? And is not their presence an important element in
predisposition to disease?

When this reflex is restored micro-organisms get no further than the
stomach. They are destroyed there by the acid gastric juices, then
only stimulated to their full and normal secretion by the presence
of a sufficiency of alkaline substance. Undigested matter having
been eliminated, micro-organisms, still existing in the intestines,
deprived of their means of subsistence, decrease, and, in time, may
cease to exist. The body no longer absorbs the toxins these produced.
To this fact may be ascribed the increase of mental energy, the
general physical betterment, the cessation of morbid cravings for
food and drink and of those of a sexual nature, which are noticed and
experienced.

What has just been stated is based not entirely on experimental
evidence but somewhat upon inference. The inference seems justified
because the excreta, more especially of the intestines, but also of the
kidneys and skin, become almost odourless and entirely inoffensive.
The solid egesta are voided thickly covered with mucus, leaving the
end of the bowel dry and clean. The sense of cleanliness can only
then be appreciated to the full, for it is internal as well external.
_Flatus_ is no longer produced. The urine is inoffensive and seems to
be materially changed in quality, as shown by chemical analysis. Uric
acid, the chlorides, and, more markedly, aromatic sulphates are reduced
in quantity.

Owing to deliberation in eating, necessitated by this new habit,
satiety occurs on the ingestion of considerably less food. By carefully
studying one’s self I believe it possible to cultivate an instinct
which will regulate not only the quantity but the quality of food that
the body may need, and that in the _normal health_ of a full-grown
body, no more food either in quantity or quality should be supplied
than suffices to supply diurnal waste. Any excess must result in
pathological processes.

Although there results enhanced pleasure in the taking of all foods,
rich and simple, and especially in the appreciation of good wines, the
quantities of these foods and beverages that suffice to fully satisfy
the appetite are much smaller than before, while there is a marked
preference for the simpler kinds of food. The writer now can imagine no
more pleasurable meal than one consisting of good brown bread, eggs,
butter, cheese, and cream. These, with fresh vegetables and a very
little fruit, form his staple diet. This tendency and preference for
simple foods is the general experience among those who have recovered
their reflexes of deglutition.

Following on the ingestion of a lessened quantity of food and on its
better assimilation, there is less waste, the egesta are voided less
frequently, sometimes only once in five to eight days.

The lower bowel is not the reservoir it formerly was. So hæmorrhoids
cease from troubling and constipation cannot exist. For this same
reason the body, at the beginning of the practice, commences to
approximate to its normal weight, increasing or decreasing as the
individual’s environment demands.

A few more words only need be said. It has been easy to state the
results of experiments and observations: but the acquiring of this
new reflex, while pursuing daily occupations, is not easy, and needs
more than a little patience and much serious thought. The habits of a
lifetime cannot be changed in a few days or weeks. The shortest time in
which the reflex has been re-established is four weeks, and this only
by avoiding conversation at meal-time and concentrating the attention
on keeping the food in the mouth until complete alkaline reduction has
taken place and sapidity has disappeared.

In closing I wish to maintain as a fact, gentlemen, of the truth of
which you will only be convinced by actual experience, that by the
restoration of this reflex and in complete dependence on its use,
there lies true health, the establishment of a condition of stable
nutrition and the possible abrogation of two great predisposing factors
of disease, mal-assimilation and mal-nutrition. Unless there be among
you, as in the “Cities of the Plain,” a parlous minority who possess
this reflex and take your food as you ought, none of you are in the
enjoyment of such health as you might have. A like punishment will be
meted out to you as was visited on those cities, for you will all be
consumed long before your day by the unnecessary combustion in your
bodies caused by the circulation in them of toxins, the product of
undigested and decomposing food.

The writer, bearing in mind the warning suggested by the Frenchman
whose donkey died as soon as he had reduced his food to a single wisp
of straw, finds that he is taking less and less food. While his mind is
open as to his arriving at the final diet of Luigi Cornaro, yet it is
easily conceivable that living a similar life of retirement in a placid
environment, it would be quite possible to do as he did. Hence the
title of this paper and the queries at the commencement.

The objects in publishing and distributing this paper are twofold: to
make the subject as widely known as possible, and to solicit the aid of
colleagues in investigating it more fully.

There is ready at the service of the general practitioner an important
and potential therapeutic agent in the saliva of his patients and in
the use _ad finem_ of their salivary digestions.

By any chance should readers of this paper wish to ask any questions,
the writer will be happy to communicate with them.

183, CALLE DEL CAPELLO NERO,
Piazza San Marco,
Venice, Italy.

_Editor’s notes._ (1) Confirmatory evidence of the correctness of
the deductions made in this paper has begun to come in from many
professional sources and notably from a famous child specialist who
avers that children would follow the natural requirements in eating
were it not for artificial food, bad example, and bad teaching.

(2) In a report of a paper read before the _Société de Biologie_,
Paris, France, March 15th, 1902, by M. Max Marckwald, of Kreuznach, “ON
DIGESTION OF MILK IN THE STOMACH OF FULL-GROWN DOGS,” the following
appears: “Hence these experiments confirm those of Horace Fletcher
and Ernest H. Van Someren on the importance of prolonged mastication”
(_translation_). Referring, as the latter statement does, to
mastication (insalivation) of liquid, it gives an important suggestion
relative to some probable causes of uncertain or defective digestion in
human nutrition.

THE CAMBRIDGE TESTS

[In connection with a report of the Cambridge Examination the writer
wishes to acknowledge the interest and assistance of Dr. Francis
Gowland Hopkins, head of the Physiological-Chemical Department of
the Physiological Laboratory of the University; Dr. George H. F.
Nuttall, in charge of the Bacteriological Section of the Pathological
Laboratory; Mr. Sidney W. Cole, Mr. Robert Barrett, and Dr. Hubert
Higgins, both for practical work in the laboratory and in serving as
test-subjects. To Dr. Higgins so much is due that it is difficult to
measure. Since our first meeting in Cambridge, Dr. Higgins has been
unremitting in his study of the subject and in consideration of its
application to human betterment. Having the altruistic temperament
inborn and not yet smothered by disappointment, the good doctor
has consecrated himself to the service of poorer humanity, and his
inspiration in so good a cause is wonderful motive power behind the
native desire to do good. The statement of Dr. Higgins' experiences in
pursuit of an Economic Nutrition is given in his own manner in the new
edition of _Glutton or Epicure_, which is being published coincidently
with this volume in the A. B. C. Life Series.

At the time we were in Cambridge, Dr. Hopkins and Mr. Cole had just
published their paper in the _Journal of Physiology_ (English),
describing their isolation of the tryptophane element of the proteid
molecule which had eluded chemists from the beginning. In tryptophane
they found embodied the odourous indol and skatol which appear so
offensively in the putrid decomposition of proteid. In the excreta of
the test-subjects in our Economic-Nutrition-Inquiry these malodorous
substances did not appear, and hence another question is opened up
to investigation relative to the putridity of human excrement under
ordinary conditions of carelessness, and the absence of putridity in
the case of nutrition accomplished by aid of thorough buccal treatment
of food preparatory to digestion.

It is a matter of interest, relative to the patience required in
science, to state that Dr. Hopkins and Mr. Cole were fourteen months
searching for the fugitive tryptophane element after they received
their first clew to its whereabouts. When isolated, tryptophane masses
in a substance having the appearance of silver, but not the solidity
of that metal.—HORACE FLETCHER.]

EXPERIMENTS UPON HUMAN NUTRITION

NOTE BY SIR MICHAEL FOSTER, K.C.B., M.P., F.R.S.

In 1901 Dr. Ernest Van Someren submitted to the British Medical
Association, and afterwards to the Congress of Physiologists at Turin,
an account of some experiments initiated by Mr. Horace Fletcher.
These experiments went to show that the processes of bodily nutrition
are very profoundly affected by the preliminary treatment of the
food-stuffs in the mouth, and indicated that great advantages follow
from the adoption of certain methods in eating. The essentials of these
special methods, stated briefly and without regard to certain important
theoretical considerations discussed by Dr. Van Someren, consist of a
specially prolonged mastication which is necessarily associated with
an insalivation of the food-stuffs much more thorough than is obtained
with ordinary habits.

The results brought to light by the preliminary experimental trials
went to show that such treatment of the food has a most important
effect upon the economy of the body, involving, in the first place, a
very notable reduction in the amount of food--and especially of proteid
food--necessary to maintain complete efficiency.

In the second place this treatment produced, in the experience of its
originators, an increase in the subjective and objective well-being
of those who practise it, and, as they believe, in their power of
resistance to the inroads of disease. These secondary effects may
indeed be almost assumed as a corollary of the first mentioned;
because there can be little doubt that the ingestion of food--and
perhaps especially of proteid food--in excess of what is, under the
best conditions, sufficient for maintenance and activity, can only be
deleterious to the organism, clogging it with waste products which may
at times be of a directly toxic nature.

In the autumn of 1901 Mr. Fletcher and Dr. Van Someren came to
Cambridge with the intention of having the matter more closely inquired
into, with the assistance of physiological experts. The matter evoked
considerable interest in Cambridge, and observations were made not only
upon those more immediately interested, but upon other individuals,
some of whom were themselves medical men and trained observers.

Certain facts were established by these observations, which, however,
are to be looked upon as still of a preliminary nature. The adoption of
the habit of thorough insalivation of the food was found in a consensus
of opinion to have an immediate and very striking effect upon appetite,
making this more discriminating, and leading to the choice of a simple
dietary, and in particular reducing the craving for flesh food. The
appetite, too, is beyond all question fully satisfied with a dietary
considerably less in amount than with ordinary habits is demanded.

Numerical data were obtained in several cases, but it is not proposed
to deal with these in detail here, as they need the supplementary study
which will be shortly referred to.

In two individuals who pushed the method to its limits it was found
that complete bodily efficiency was maintained for some weeks upon a
dietary which had a total energy value of less than one-half of that
usually taken, and comprised little more than one-third of the proteid
consumed by the average man.

It may be doubted if continued efficiency could be maintained with such
low values as these, and very prolonged observations would be necessary
to establish the facts. But all subjects of the experiments who
applied the principles intelligently agreed in finding a very marked
reduction in their needs, and experienced an increase in their sense of
well-being and an increase in their working powers.

One fact, fully confirmed by the Cambridge observations, consists in
the effect of the special habits described upon the waste products of
the bowel. These are greatly reduced in amount, as might be expected;
but they are also markedly changed in character, becoming odourless and
inoffensive, and assuming a condition which suggests that the intestine
is in a healthier and more aseptic condition than is the case under
ordinary circumstances.

Although the experiments hitherto made are, as already stated, only
preliminary in nature and limited in scope, they establish beyond all
question that a full and careful study of the matter is urgently called
for.

For this fuller study the Cambridge laboratories do not possess at
present either the necessary equipment or the funds to provide it. For
the detailed study of the physical efficiency of a man under varying
conditions, elaborate and expensive apparatus is required; and the
advantages claimed for the special treatment of the food just discussed
can only be fully tested by prolonged and laborious experiments calling
for a considerable staff of workers.

It is of great importance that the mind of the lay public should
be disabused of the idea that medical science is possessed of final
information concerning questions of nutrition. This is very far indeed
from being the case. Human nutrition involves highly complex factors,
and the scientific basis for our knowledge of the subject is but small;
where questions of diet are concerned, medical teaching, no less than
popular practice, is to a great extent based upon empiricism.

But the scientific and social importance of the question is clearly
immense, and it is greatly to be desired that its study should be
encouraged.

M. FOSTER.

April 26th, 1902.

REPORT OF A PLAN FOR THE INSTITUTION OF AN INTERNATIONAL INQUIRY INTO
THE SUBJECT OF HUMAN NUTRITION

[Sir Michael Foster’s “Note” (preceding) and Professor Chittenden’s
article in the _Popular Science Monthly_ (following), which form a
part of this book, show a common want of exact knowledge relative to
human nutrition not at all creditable to human intelligence at the
beginning of the twentieth century; but they both offer hope of relief
from this discreditable stigma in systematic study of the question.
For this purpose an international inquiry was proposed, a plan was
drawn up under advice of Sir Michael Foster, and the matter was given
to the writer to promote by the best means available.

The Carnegie Institution seemed, at the time, the most likely
supporter of such a scheme; but owing to an embarrassment of
applications for support of American science needs, it was considered
best not to attempt any foreign or even international benefaction, for
the present at least, and hence other means of furthering the inquiry
were sought.

The invitation of Professor Chittenden to repeat the demonstration
of food-economy made by the author and Dr. Van Someren at Cambridge,
England, of which Sir Michael Foster’s “Note” treats, at the
laboratories of the Sheffield Scientific School of Yale University,
led to the discovery that New Haven already possessed an equipment
suitable for the inquiry much more complete than the plan Professor
Foster had outlined as being desirable.

At Yale were found not only a very well-adapted chemico-physiological
laboratory with some of the most active and scientifically respected
research talent of the world in charge, but the laboratory stood only
three minutes away from one of the best furnished gymnasiums in the
world, under a director who is an M. D. of twenty years' experience,
as well as a famous athlete and author of an athletic manual. It so
happened that this gymnasium was especially suited for assisting in
a research into the very causes of human efficiency, or lack of it,
which nutrition is supposed to affect.

Only forty minutes from New Haven by rail,--a distance not greater,
as measured by time separation, than from one side of London to the
other,--at Middletown, Conn., stood also the recently completed
calorimeter of Professors Atwater and Benedict ready for making a
calorimetric trial-balance measurement of metabolism attained and
chemically estimated in the tests at New Haven.

After the Yale demonstration, of which Professor Chittenden’s article,
previously mentioned, treats, the author responded to an invitation
from Professor Atwater and submitted himself to a 32-hour confinement
in the calorimeter for confirmation of the results obtained at New
Haven.

This experience in the calorimeter at Middletown was very significant
and instructive. The author was the first test-subject used in the
newly completed calorimeter. The oxygen-measuring attachment of Dr.
Benedict that completed the apparatus and gave a complete trial
balance of the metabolism of the subject under examination was as
yet untried, but it proved its integrity within the fraction of one
per cent and registered as accurately as necessary for all practical
purposes. So much for the machine; but it measured a result which is
of the greatest importance to the human race. The author had just
demonstrated the possibility of running the human machine on half the
heat, on one-third of the fuel, and with only one-tenth of the waste,
as represented by the waste, or ashes of digestion. Not only was this
done while in pursuit of the ordinary activity of present-day life,
but under stress of 'Varsity-Crew exercise, as reported by Professor
Chittenden and Dr. Anderson. Had this demonstration been made relative
to steam engines or electrical motors, the information would have been
revolutionary in establishing new values for things industrial and
commercial.

Its significance relative to human profitable possibilities is even
more important than if related to steam or electrical power. The
possibility of economy in the human machine gives also a hope of
immunity from the common diseases which now afflict mankind.

The trial of the calorimeter as a measuring machine and the trial
balance of the economic metabolism which the author had attained
by five years of careful attention to the natural requirements of
nutrition were epoch-making events coincidently related, and for them
the author here makes this distinguished claim--not on account of any
accomplishment of himself, but as a promise of great possibilities for
human betterment.

Here follows a reproduction of the plan just referred to, with
_fac-simile_ of the signatures of the distinguished physiologists
who approved the plan and consented to serve as “Assessors.” To this
list should have been added the name of Professor Ozawa, professor of
physiology at the University of Tokio, Japan; but time and distance
did not permit gaining the required understanding and assent.
Professor Ozawa’s connection with the inquiry would make it not only
international but interhemispherical and interracial as well, and this
possibility of scientific coördination and coöperation is typical of
the harmonising wave that is fast enveloping the earth for the benefit
of mankind.

I give a copy of the document entire, with estimates of cost,
etc., just as it was originally drawn and intended only as a trial
suggestion, to be modified by circumstances.—HORACE FLETCHER.]

PROPOSAL TO FOUND AN INTERNATIONAL LABORATORY OF RESEARCH FOR THE
STUDY OF NUTRITION IN ALL ITS ASPECTS

Notwithstanding the enormous development which the study of
Experimental Physiology has undergone during the last half-century, and
the constant multiplication of physiological laboratories fitted in
a manner which enables them to be used as places of research as well
as of instruction in the methods of physiological inquiry, it has
appeared to many physiologists that a great need remains to be supplied
by the establishment of an International Laboratory of Research,
devoted primarily, if not exclusively, to the investigation of problems
connected with the Nutrition of the Animal, and particularly of Human
Organisms,--studies particularly, and in the first instance, from the
point of view of the relation of the food consumed by the animal body
to its output of energy, either in the form of heat or mechanical work.

The reason for establishing such a laboratory, available for the use
of investigations of all nations, is to be found in the fact that the
researches which are now called for, in order to place upon a firm
foundation our knowledge of food and its relations to the activity of
the organism, necessitates an assemblage of apparatus and machinery
so specialised and so costly that they are not to be found collected
together even in the best equipped of the physiological laboratories
of Europe or America, which all subserve in the first instance the
purposes of systematic instruction. Undoubtedly, unquestionably,
certain of the great and costly appliances of research are to be found
in particular laboratories, as, for instance, in those of Berlin,
Munich, Paris, and Turin, but there certainly exists no laboratory
in which the investigator can find assembled under one roof all
the specially fitted chemical, physical, and even bacteriological
appliances which he may need to employ in the investigation of the
Phenomena of Nutrition.

A more precise conception of the nature of the proposed laboratory
may be formed if reference is made to certain groups of appliances
which such a laboratory should possess and be able to place at the
disposal of the scientific men coming to it for facilities which may be
denied them at home. It should possess a complete set of respiration
chambers of various types, and especially should be provided with the
“Atwater Respiration Apparatus;” the most perfect appliances for the
analyses of gases should be available; it should be provided with the
most perfect calorimeters of various types, both for the investigation
of the calorimetric value of the foods experimented on, and for the
determination of the heat produced by man or by the lower animals,--the
subjects of observation. The laboratory should possess, besides, the
most perfect appliances for the measurement of work done by man and
by animals (“ergostat,” “ergograph”), and a set of balances of the
highest perfection capable of weighing with accuracy very heavy loads.
These characteristic appliances of a laboratory specially designed for
placing our knowledge of Animal Nutrition on a thoroughly sound basis
must be superadded to the ordinary means for pursuing with success
researches in Pure Organic, Physiological, and Physical Chemistry, as
well as in Bacteriology.

OUTLINE OF THE PROPOSED SUBJECTS OF RESEARCH TO BE UNDERTAKEN IN THE
PROPOSED INTERNATIONAL LABORATORY

1. To determine with greater precision than has yet been possible the
efficiency of the animal organism considered as a machine in which
potential energy of the organic constituents of food is converted
into mechanical work. The knowledge that we already possess has shown
that in the animal we have an engine infinitely more efficient as a
utiliser of the potential energy supplied to it than any appliance yet
constructed, or which we can, in the present state of physical science,
construct. A still more precise study of the actual efficiency of the
animal as a whole, as well as of certain of the vital organs which are
mainly concerned in mechanical work, and a more thorough investigation
of the processes whereby--for instance, in the muscles--the potential
energy of stored-up chemical compounds is, as appears certain, directly
converted into mechanical work, is not only desirable in the interest
of the ultimate object of the work of the Laboratory, but possesses a
high degree of theoretical interest, even from the point of view of
Pure Physics. To sum up: One of the first objects of the investigations
to be carried out in the projected Laboratory should be “the more
precise determination of the minimum transformation of energy which
corresponds to mean and accurately determined conditions of the animal
body, and of that of man in particular.”

2. We are acquainted with the fact that the potential energy which
is utilised by the animal is supplied to it with the least wear and
tear to, or strain upon, its mechanism by non-nitrogenous organic
constituents of food which must belong to the groups of starches and
sugars or fats, but that the continued existence of the organism
demands, as an essential condition, the introduction of a certain
proportion of albuminous matter. In spite of numerous very fine
investigations on this subject, the yet more precise determination
of the minimum quantity of the albuminous constituents which are
absolutely necessary or desirable, under the most varying conditions,
is eminently desirable, especially in the light of recently recorded
facts, amongst which are those to be referred to under 3 (following):—

3. Certain very noteworthy observations made by Messrs. Horace Fletcher
and Ernest H. Van Someren have shown that an excessively prolonged
mastication and insalivation of food leads to remarkable results in
respect to the diminution of the total quantity of food necessary to
keep the body in a state of health, and to, as is alleged, a remarkable
improvement in the digestive functions as well as of the general
health of the individual. It appears highly important thoroughly to
investigate the remarkable phenomena discovered by Messrs. Fletcher and
Van Someren, and to determine how far they may lead to a modification
of or improvement in the dietary of healthy individuals and of persons
in a state of disease.

4. Indeed, it may truly be said that the average diet of man, that is
to say, the absolute and relative amount of certain food-stuffs on
which an average man should live, is at present, to a large extent,
determined in an empirical manner. It is most necessary that this
should be determined in an exact manner, since it is at least possible
that a more complete knowledge may reveal that the good results
thus obtained empirically are only reached by means of an excess of
one element being counterbalanced by excess of another element, and
thus open up a way to considerable economy. The changes needed for
variations from the average, to meet certain conditions, are also at
present, to a very large extent, determined empirically, and these also
most certainly ought to be determined in an absolutely exact manner.

5. The researches of Pawlow on the conditions which influence the
activity of the secreting glands of the organs of digestion, upon the
relation of their activity to the nature of the food ingested, upon
the influence exerted by the secretion of the glands situated in one
part of the alimentary canal, upon the activity of glands situated
lower down, indicate lines of research only recently opened out, but
the importance of which in reference to the problems of nutrition is
probably great.

6. Similarly, the facts which have in recent times been ascertained
in reference to the remarkable influence exerted by the so-called
“internal secretion” of certain ductless glands on the general
metabolism, the part played by the pancreas in reference to the
transformations of sugar in the body indicate yet other lines of
research to be carried out in connection with the main inquiry.

In conclusion: The final problem of the work of the proposed Laboratory
will be to ascertain the conditions which will “render it possible to
obtain from the human machine, under varying conditions, the highest
efficiency at the least cost.”

The value of results which may be thus obtained, considered from the
point of view of social, political, and administrative economy, is
hardly to be exaggerated.

SUGGESTIONS AS TO STAFF AND PERSONNEL OF THE PROPOSED INTERNATIONAL
LABORATORY

For the coördination and general direction of the several
investigations, the services of an eminent physiological chemist
(preferably one having the principal European languages at his command)
is essential.

Such a director would need at least two efficient permanent technical
assistants, as for instance, one to deal with the problems of Organic
Chemistry, and another competent to deal with the problems of Physical
Chemistry. Other assistants might be necessary, but it would probably
be desirable that the Institute should have the power of subsidising,
for a longer or shorter period, men who would undertake special
investigations in coördination with the general work, and who would
thus be, as it were, temporary assistants. This would be quite apart
from the general hospitality of the Laboratory offered by the Institute
to other investigators.

ESTIMATES FOR THE PROPOSED LABORATORY

INITIAL OUTLAY

Director $5,000 $5,000
Permanent and Temporary Assistants 7,500 to 10,000
Other General Maintenance 5,000 to 7,500
——————— ——————
— $17,500 $22,500

With regard to the second item, the permanent assistants would be
required at the outset, but the temporary assistants would be taken on
as opportunity offered. Less than even the lower estimate might suffice
at first.

Regarding the third item, also, the maximum might not be required in
the beginning.

SUGGESTIONS AS TO DESIRABILITY OF LOCATION

The place fitted for the establishment of an International Institute
should be one which can be reached with comparative facility by
investigators of the different nationalities. It must be one free
from the objections due to national susceptibilities. It should also
be, if possible, a place agreeable to live in; a place where work can
be carried on through the year; and a place where expenses, both the
personal expenses of the investigators, and the general expenses of
the Institute, are not excessive. Venice has been suggested as a place
fulfilling the above requirements. It can be reached readily from
all parts of Europe, and is as accessible to Americans as any other
European city. Living is very cheap, and, indeed, all expenses are very
moderate.

On sea level itself, Venice is within near distance of very high
altitude, and hence offers facilities for the study of the effects
of climatic influence on nutrition. It is also sufficiently near the
Regina Margherita Laboratory, on Monte Rosa, to enable the observations
made at the two places to be coördinated. Venice is, moreover, a
cosmopolitan centre; and persons of many different nations and races
might readily be obtained as subjects for observation and experiment.

On the other hand, it may be regarded as essential to the complete
success of the proposed Institute that both the director and those
engaged in investigation should have ample opportunities of ready and
frequent intercourse with eminent men engaged in investigation in
Physics, Chemistry, and the allied sciences. The help which is thus
gained by intercourse with men at the very head of various scientific
inquiry cannot be supplied in any other way. There is also an urgent
reason for ready access to a most thoroughly equipped scientific
library. It is also essential that the Institute should have facility
of obtaining, or of getting constructed, with the least possible delay
such apparatus as it might need. These essentials cannot be supplied
otherwhere than in great centres of scientific activity. A small
university cannot supply them. If they are insisted on, the Institute
must be located in a place which has metropolitan distinction and holds
not only a large but an active university. The choice of a situation,
from this point of view, in Europe, is thus almost limited to such
places as Paris, Berlin, Vienna, or London. Of these London probably
best recommends itself for international purposes.

But, on the other hand, London is distinctly an expensive place to live
in. Indeed, all expenses there are great, and the same may be said of
any great metropolitan centre. Moreover, London cannot be reached from
the countries of Europe without sea transit.

The choice between such a place as London and such a place as Venice
must depend upon the relative weight attached, on the one hand, to the
scientific advantages dwelt on above, and, on the other hand, to the
advantages other than scientific.

SUGGESTIONS AS TO MANAGEMENT OF THE PROPOSED INTERNATIONAL INSTITUTE

It is proposed that: First, there should be a small body of trustees
who should undertake the financial responsibility; and, Second, a
board of scientific assessors, representing several nations, who, in
conjunction with the director, should exercise general supervision
of the work of the Institute. Such a board need meet only at rare
intervals, much being done by way of correspondence. The expenses which
the members incur in the exercise of their functions ought to be met
out of the funds of the Institute.

The following have expressed willingness to act as scientific
assessors:—

[Illustration: Signatures]

NATIONALITY AND SCIENTIFIC TITLES OF OUR BOARD OF SCIENTIFIC ASSESSORS

SIR MICHAEL FOSTER, M.D., K.C.B., F.R.S., M.P., etc. Late Professor of
Physiology, University of Cambridge, England; Secretary of the Royal
Society; Permanent Honorary President of the International Congress of
Physiologists, etc.

DR. PROFESSOR ANGELO MOSSO. Professor of Physiology, University of
Turin, Italy; Director of the Regina Margherita Biological Station on
the summit of Monte Rosa, etc.

DR. PROFESSOR HUGO KRONECKER. Professor of Physiology, University of
Berne, Berne, Switzerland, etc.

DR. PROFESSOR N. ZUNTZ. Professor of Physiology, Berlin, Germany, etc.

DR. PROFESSOR PAUL HEGER. Professor of Physiology, Brussels, Belgium;
Director of the Solvay Sociological Institute, Brussels.

DR. PROFESSOR A. DASTRE. Professor of Physiology, Universitie de la
Sorbonne, Paris, France, etc.

DR. PROFESSOR HENRY PICKERING BOWDITCH, Professor of Physiology,
Harvard Medical School; Second President American Physiological
Society; President of the Children’s Aid Society, Boston, Mass., etc.

PROFESSOR RUSSELL H. CHITTENDEN. Director Sheffield Scientific School
of Yale University; Professor of Physiological Chemistry in Yale;
Present President of the American Physiological Society, etc.

DR. PROFESSOR WILLIAM H. WELCH. Professor of Pathology in Johns
Hopkins University, Baltimore, Maryland; President of the Rockefeller
Institute of Preventive Medicine, etc.

DR. PROFESSOR J. P. PAWLOW. Director of the Department of Experimental
Physiology in the Russian Imperial Military School of Medicine, etc.

PERSISTENT SCIENTIFIC DOUBTS

[Notwithstanding the report of the Cambridge examination of the
claims for an economic nutrition advanced by the authors, American
physiologists were still doubtful if a nitrogenous economy like that
reported could be maintained, and the writer was invited to submit
to further tests at the Physiological Laboratory of Yale University,
under direction of Professor Russell H. Chittenden, Director of
the Sheffield Scientific School, and President of the American
Physiological Society, and Dr. Lafayette B. Mendel.

The following article, first published in the _Popular Science
Monthly_, June, 1903, is a report of that test, and indicates a
desire to carry the investigation further to include a variety of
test-subjects.

In response to Professor Chittenden’s request, the Trustees of the
Bache Fund of the National Academy of Sciences appropriated $1000
towards a more extended inquiry; and other means having been assured,
a project of experiments was taken under consideration.

One of the difficulties encountered was the control of test-subjects
for a sufficiently long time to make conclusive estimates relative
to the minimum needs of nitrogenous food in relation to the common
occupations of life. Few if any volunteers, with the leisure and
interest fortunately possessed by the writer, were available outside
the laboratory force itself, and there were serious objections to
using for test-subjects the same persons who did the chemical analyses
and estimated the results.

In this dilemma the good fortune of a meeting with Surgeon-General
O’Reilly of the United States Army and with General Leonard Wood--the
former on his way to Madrid to attend a medical congress, and the
latter _en route_ to the Philippines to take command there--happened
to the writer on the S. S. _Commonwealth_, on a voyage to Italy in
April, 1903.

Both these officers are medical men and research enthusiasts. They had
fought yellow fever together, in coöperation with martyr Dr. Major
Walter Reed, in Cuba, and the fame of their success was being talked
of as one of the great triumphs of pathologic, or hygienic, science at
the time of the meeting.

There was ample time on the steamer to discuss a subject of such
mutual and general interest, and both officers had had, in service,
experiences that led them to believe that the results obtained by the
writer and his colleagues were the common possibilities of all persons
under right conditions of alimentation.

General O’Reilly was of the opinion that the corps he commanded
could furnish intelligent and earnest test-subjects for nutrition
investigation, as it did in the yellow fever case. In the yellow fever
investigation privates and officers alike had volunteered to act as
test-subjects, even though their lives were at stake and many had
already been sacrificed. It is to their great honour, also, that they
refused to receive the bounty that was offered for test-subjects,
preferring to serve science and humanity freely as volunteers rather
than sell themselves as experimental risks. From such material General
O’Reilly was sure that capable assistants could be secured to test the
not at all dangerous or disagreeable economies of nutrition that the
projected inquiry wished to solve.

Armed with letters of recommendation to the President and to
the Secretary of War from General Wood, and an invitation from
Surgeon-General O’Reilly to call on him if coöperation on his part
were desired, the writer returned to the United States and consulted
with Professors Chittenden and Bowditch relative to the desirability
of army coöperation. It was believed to be just the thing wanted to
facilitate the inquiry, and the writer proceeded to Washington to
effect the combination.

General O’Reilly had already had the matter under consideration and
was quite ready to draw up a project for presentation to the Secretary
of War when Mr. Root should return to Washington from his summer
vacation.

Twenty privates and three non-commissioned officers of the Hospital
Corps of the United States Army under command of Dr. Lieutenant
Wallace DeWitt are now quartered at New Haven in coöperation with
the staff of the Sheffield Scientific School. It is the intention
to learn, if possible, how little nitrogen is necessary to secure
the best human efficiency; and also, if possible, to ascertain some
measure of the evil effects of an excess of nitrogenous food as well
as excess of food in general upon human efficiency.

The writer is grateful for the good fortune of being able to be of
service in a development of interest in a subject which is of vital
importance to the human race. He has enjoyed the benefits of an
economic nutrition and knows its value.

The practical proof of a subject of personal application must come
from such personal application. Each person must be his own doctor and
his own scientist in the matter of his alimentation or he runs the
risk of running amuck in his health economy. There is not so much to
learn, neither is there very much to do to insure right alimentation,
perfect digestion, and continuous good health; but the little required
of us must be attended to with no lapses of attention.—HORACE
FLETCHER.]

PHYSIOLOGICAL ECONOMY IN NUTRITION

BY RUSSELL H. CHITTENDEN

_Director of the Sheffield Scientific School of Yale University_

Among the many problems awaiting solution, none is of greater
importance for the welfare of the individual and of the race than
that which relates to the proper nutrition of the body. Man eats to
live and to gain strength for his daily work, and without sufficient
nutriment the machinery of the body cannot be run smoothly or with
proper efficiency. The taking of an excess of food, on the other hand,
is just as harmful as insufficient nourishment, involving, as it does,
not only wasteful expenditure but, what is even of greater moment, an
expenditure of energy on the part of the body, which may in the long
run prove disastrous. While it is the function of food to supply the
material from which the body can derive the necessary energy for its
varied activities, any excess of food over and above what is needed to
make good the loss incidental to life and daily activity is just so
much of an incubus, which is bound to detract from the smooth running
of the machinery and to diminish the fitness of the body for performing
its normal functions.

A proper physiological condition begets a moral, mental, and physical
fitness which cannot be attained in any other way. Further, it must be
remembered that lack of a proper physiological condition of the body
is more broadly responsible for moral, social, mental, and physical
ills than any other factor that can be named. Poverty and vice on
ultimate analysis may often be traced to a perversion of nutrition.
A healthy state of the body is a necessary concomitant of mental and
moral vigour, as well as of physical strength. Abnormal methods of
living are often the accompaniment or forerunner of vicious tastes
that might never have been developed under more strictly physiological
conditions. Health, strength (mental and physical), and moral tone
alike depend upon the proper fulfilment of the laws of nature, and it
is the manifest duty of a people hoping for the fullest development
of physical, mental, and moral strength to ascertain the character of
these laws with a view to their proper observance. Poverty, crime,
physical ills, and a blunted or perverted moral sense are the penalties
we may be called upon to pay for the disobedience to Nature’s laws;
penalties which not only _we_ may have to pay, but which may be passed
down to succeeding generations, thereby influencing the lives of those
yet unborn.

There is to-day great need for a thorough physiological study of those
laws of nutrition which constitute the foundation of good living.
It is a subject full of interest and promise for the sociologist
and economist, as well as for the physiologist. We need a far more
complete knowledge than we possess at present of the laws governing
nutrition; we need fuller knowledge of the methods by which the most
complete, satisfactory, and economical utilisation of the diet can be
obtained; we need to know more concerning the minimum diet and the
minimum amount of proteid or albuminous foods on which health, mental
and physical vigour can be permanently maintained; we need to know
more fully concerning the influence of various forms of food on growth
and recuperative power; we need more complete knowledge regarding the
rôle of various dietetic and digestive habits, fixed or acquired; the
effects of thorough mastication, insalivation, and the influence of
two versus three meals a day upon the utilisation of food and hence
upon the bodily health. Further, we need more concise information as
to the effect of the mental state upon digestion and nutrition. These
and many other problems of a like nature confront us when we attempt
to trace the influence of a proper nutrition upon the condition of the
body. These problems, however, all admit of solution, and in their
solution undoubtedly lies the remedy for many of the personal ills of
mankind.

The foregoing thoughts have been suggested by observations recently
made in the writer’s laboratory on the amount and character of the
food actually required by a healthy man in the maintenance of bodily
equilibrium in periods of rest and physical work. Our ideas at present
are based primarily upon observations as to what civilised peoples are
accustomed to do, and not upon what they need to do in order to meet
the demands made upon the body. Sir William Roberts has well said that
the palate is the dietetic conscience, but he adds that there are many
misfit palates, and we may well query whether our dietetic consciences
have not become generally perverted through a false mode of living. The
well-nigh universal habit of catering to our appetite on all occasions,
of bowing to the fancied dictates of our palates even to the extent of
satiety, and without regard to the physiological needs of the body,
may quite naturally have resulted in a false standard of living, in
which we have departed widely from the proper laws of nutrition.
Statistical studies carried out on large groups of individuals by
various physiologists have led to the general acceptance of dietary
standards, such as those proposed by Voit, of Munich, and Atwater in
this country. Thus the Voit diet for a man doing moderate work is 118
grams of proteid or albuminous food, 56 grams of fat, and 500 grams
of carbohydrates, such as sugar and starch, with a total fuel value
of 3,055 large calories or heat units per day. With hard work, Voit
increases the daily requirement to 145 grams of proteid, 160 grams of
fat, and 450 grams of carbohydrates, with a total fuel value of 3,370
large calories. Atwater, on the other hand, from his large number of
observations, is inclined to place the daily proteid requirement at
125 grams, with sufficient fat and carbohydrate to equal a total fuel
value of 3,500 large calories for a man doing a moderate amount of
work; while for a man at hard work the daily diet is increased to 150
grams of proteid, and with fats and carbohydrates to yield a total
fuel value of 4,500 large calories. These standards are very generally
accepted as being the requirement for the average individual under the
given conditions of work, and it may be that these figures actually
represent the daily needs of the body. Suppose, on the other hand, that
we have in these figures false standards, or, in other words, that the
quantities of food-stuffs called for are altogether larger than the
actual demands of the body require. In this case there is a positive
waste of valuable food material which we may calculate in dollars
and cents; a loss of income incurred daily which might be expended
more profitably in other directions. To the wage-earner with a large
family, who must of necessity husband his resources, there is in our
hypothesis a suggestion of material gain not to be disregarded. The
money thus saved might be expended for the education of the children,
for the purchase of household treasures tending to elevate the moral
and mental state of the occupants, or in many other ways that the
imagination can easily supply. This kind of saving, however, is purely
a question of economy, and in some strata of society would be objected
to as indicative of a condition of sordidness. It has come to be a
part of our personal pride to have a well-supplied table, and to eat
largely and freely of the good things provided. The poorer man takes
pride in furnishing his family with a diet rich in expensive articles
of food, and imagines that by so doing he is inciting them to heartier
consumption and to increased health and strength. He would be ashamed
to save in this way, under the honest belief that by so doing he
might endanger the health of his dear ones. But let us suppose that
this hypothetical waste of food is not merely uneconomical, that it is
undesirable for other and weightier reasons. Indeed, let us suppose
that this unnecessary consumption of food is distinctly harmful to the
body, that it is physiologically uneconomical, and that in our efforts
to maintain a high degree of efficiency we are in reality putting upon
the machinery of the body a heavy and entirely uncalled-for strain,
which is bound to prove more or less detrimental. If there is truth in
this assumption, our hypothesis takes on a deeper significance, and we
may well inquire whether there are any reasonable grounds for doubting
the accuracy of our present dietary standards.

In this connection it is to be remembered that the food of mankind may
be classified under three heads, viz., _proteid or albuminous_, such
as meat, eggs, casein of milk, gluten of bread, and various vegetable
proteids; _carbohydrates_, as sugar and the starches of our cereals,
and _fats_, including those of both animal and vegetable origin. The
proteids are characterised by containing nitrogen (about 16 per cent),
while the fats and carbohydrates contain only carbon, hydrogen, and
oxygen. The two latter classes of food-stuffs are burned up in the
body, when completely utilised, to carbonic acid (a gas) and water,
while the proteid foods, beside yielding carbonic acid and water,
give off practically all of their nitrogen in the form of crystalline
nitrogenous products in the excreta of the body. Proteid foods have a
particular function to perform, viz., to supply the waste of proteid
matter from the active tissues of the body, and this function can be
performed only by the proteid foods; hence the latter are essential
food-stuffs without which the body cannot long survive. Fats and
carbohydrates, on the other hand, are mainly of value for the energy
they yield on oxidation, and in this connection it is to be remembered
that the fuel value of fats per gram is much larger than that of
carbohydrates, viz., 9.3: 4.1, or more than twice as great. Further,
it is to be noted that the various food-stuffs cannot be utilised
directly by the body, but they must first be digested, then absorbed
and assimilated, after which they gradually, in their changed form,
undergo decomposition with liberation of their contained energy, which
may manifest itself in the form of heat or of mechanical work. The
thoroughness with which foods are digested and utilised in the body
must therefore count for a great deal in determining their dietetic or
nutritive value. Moreover, it is easy to see how an excess of proteid
food will give rise to a large proportion of nitrogenous waste matter,
which, floating through the system prior to excretion, may, by acting
on the nervous system and other parts of the body, produce disagreeable
results. A mere excess of food, even of the non-nitrogenous variety,
must entail a large amount of unnecessary work, thereby using up
a proportional amount of energy for its own disposal, since once
introduced into the body it must be digested and absorbed, otherwise it
undergoes fermentation and putrefaction in the stomach and intestines,
causing countless troubles. When absorbed in quantities beyond the real
needs of the body, it may be temporarily deposited as fat; but why
load up the system with unnecessary material, thereby interfering with
the free running of the machinery? In other words, it is very evident
that the taking in of food in quantities beyond the physiological
requirements is undesirable, and may prove exceedingly injurious. It
is truly uneconomical, and defeats the very ends we aim to attain.
Instead of adding to the bodily vigour and increasing the fitness of
the organism to do its daily work, we are really hampering the delicate
mechanism, upon the smooth running of which so much depends.

Why, now, should we assume that a daily diet of over 100 grams of
proteid, with fats and carbohydrates sufficient to make up a fuel
value of over 3,000 large calories, is a necessary requisite for
bodily vigour and physical and mental fitness? Mainly because of the
supposition that true dietary standards may be learned by observing
the relative amounts of nutrients actually consumed by a large number
of individuals so situated that the choice of food is unrestricted.
But this does not constitute very sound evidence. It certainly is not
above criticism. We may well ask ourselves whether man has yet learned
wisdom with regard to himself, and whether his instincts or appetites
are to be entirely trusted as safe guides to follow in the matter
of his own nutrition. The experiments of Kumagawa, Sivén, and other
physiologists, have certainly shown that men may live and thrive, for
a time at least, on amounts of proteid per day equal to only one-half
and one-quarter the amount called for in the Voit standard. Sivén’s
experiments, in particular, certainly indicate that the human organism
can maintain itself in nitrogenous equilibrium with far smaller amounts
of proteid in the diet than is ordinarily taught, and, further, that
this condition can be attained without unduly increasing the total
calories of the food intake. Such investigations, however, have always
called forth critical comment from writers on nutrition, indicating
a reluctance to depart from the current doctrines of the Voit or
Munich school; and, indeed, it may justly be claimed that the ordinary
nutrition experiments, extending over short periods of time, are not
entirely adequate to prove the effect of a given set of conditions when
the latter are continued for months or years. Thus, Schäfer writes:
“It may be doubted whether a diet which includes considerably less
proteid than 100 grams for the twenty-four hours could maintain a man
of average size and weight for an indefinite time. It has frequently
been asserted that many Asiatics consume a very much smaller proportion
of proteid than is the case with Europeans. The inhabitants of India,
Japan, and China chiefly consume rice as the normal constituent of
their diet, which contains relatively little proteid; and this has
been advanced as an argument in favour of the view that the minimal
amount of proteid is much less than that ordinarily given as essential
to the maintenance of nutritive equilibrium. It must, however, be
stated that we have no definite statistics to show that, in proportion
to their body-weight, Asiatics doing the same amount of work as
Europeans require a less amount of proteids; indeed such evidence as is
forthcoming is rather in favor of the opposite view.” This statement is
typical of the attitude of physiologists in general on this important
subject. Why not candidly admit that the matter is in doubt, and,
with a due recognition of the importance of the subject, attempt to
ascertain the real truth of the matter?

The writer has had in his laboratory for several months past a
gentleman (H. F.) who has for some five years, in pursuit of a study
of the subject of human nutrition, practised a certain degree of
abstinence in the taking of food and attained important economy with,
as he believes, great gain in bodily and mental vigour, and with marked
improvement in his general health. Under his new method of living he
finds himself possessed of a peculiar fitness for work of all kinds,
and with freedom from the ordinary fatigue incidental to extra physical
exertion. In using the word abstinence possibly a wrong impression
is given, for the habits of life now followed have resulted in the
disappearance of the ordinary craving for food. In other words, the
gentleman in question fully satisfies his appetite, but no longer
desires the amount of food consumed by most individuals.

For a period of thirteen days, in January, he was under observation in
the writer’s laboratory, his excretions being analysed daily with a
view to ascertaining the exact amount of proteid consumed. The results
showed that the average daily amount of proteid metabolised was 41.25
grams, the body-weight (165 pounds) remaining practically constant.
Especially noteworthy, also, was the very complete utilisation of the
proteid food during this period of observation. It will be observed
here that the daily amount of proteid food taken was less than one half
that of the minimum Voit standard, and it should also be mentioned that
this apparent deficiency in proteid food was not made good by any large
consumption of fats or carbohydrates. Further, there was no restriction
in diet. On the contrary, there was perfect freedom of choice, and the
instructions given were to follow his usual dietetic habits. Analysis
of the excretions showed an output of nitrogen equal to the breaking
down of 41.25 grams of proteid per day as an average, the extremes
being 33.06 grams and 47.05 grams of proteid.

In February a more thorough series of observations was made, involving
a careful analysis of the daily diet, together with analysis of
the excreta, so that not alone the proteid consumption might be
ascertained, but likewise the total intake of fats and carbohydrates.
The diet consumed was quite simple, and consisted merely of a prepared
cereal food, milk, and maple sugar. This diet was taken twice a day
for seven days, and was selected by the subject as giving sufficient
variety for his needs and quite in accord with his taste. No attempt
was made to conform to any given standard of quantity, but the subject
took each day such amounts of the above foods as his appetite craved.
Each portion taken, however, was carefully weighed in the laboratory,
the chemical composition of the food determined, and the fuel value
calculated by the usual methods.

The following table gives the daily intake of proteids, fats, and
carbohydrates for six days, together with the calculated fuel value,
and also the nitrogen intake, together with the nitrogen output through
the excreta. Many other data were obtained showing diminished excretion
of uric acid, ethereal sulphates, phosphoric acid, etc., but they need
not be discussed here.

═════════╤════════════════════════════════════════╤═══════════════════
│ Intake │ Output of Nitrogen
├————————┬————-┬——————-┬————————┬————————┼—————┼——————-┼—————
│Proteids│Fats │Carbohy│Calories│Nitrogen│Urine│ Fæces │Total
————————-┼————————┼—————┼——————-┼————————┼————————┼————-┼——————-┼————-
│ Grams │Grams│ Grams │ │ Grams │Grams│ Grams │Grams
Feb. 2 │ 31.3 │25.3 │ 125.4 │ 900 │ 5.02 │5.27 │0.18 │5.45
3 │ 46.8 │40.4 │ 266.2 │ 1690 │ 7.50 │6.24 │0.81* │7.05
4 │ 48.0 │38.1 │ 283.0 │ 1747 │ 7.70 │5.53 │0.81* │6.34
5 │ 50.0 │40.6 │ 269.0 │ 1711 │ 8.00 │6.44 │0.81* │7.25
6 │ 47.0 │41.5 │ 267.0 │ 1737 │ 7.49 │6.83 │0.81* │7.64
7 │ 46.5 │39.8 │ 307.3 │ 1852 │ 7.44 │7.50 │0.17 │7.67
————————-┼————————┼—————┼——————-┼————————┼————————┼————-┼——————-┼—————
Daily Av.│ 44.9 │38.0 │ 253.0 │ 1606 │ 7.19 │6.30 │0.60 │6.90
═════════╧════════╧═════╧═══════╧════════╧════════╧═════╧═══════╧═════
*Average of the four days.

The main things to be noted in these results are, first, that the
total daily consumption of proteid amounted on an average to only 45
grams, and that the fat and carbohydrate were taken in quantities
only sufficient to bring the total fuel value of the daily food up to
a little more than 1,600 large calories. If, however, we eliminate
the first day, when for some reason the subject took an unusually
small amount of food, these figures are increased somewhat, but they
are ridiculously low compared with the ordinarily accepted dietary
standards. When we recall that the Voit standard demands at least 118
grams of proteid and a total fuel value of 3,000 large calories daily,
we appreciate at once the full significance of the above figures. But
it may be asked, was this diet at all adequate for the needs of the
body--sufficient for a man weighing 165 pounds? In reply, it may be
said that the appetite was satisfied, and that the subject had full
freedom to take more food if he so desired. To give a physiological
answer, it may be said that the body-weight remained practically
constant throughout the seven days' period, and further, it will be
observed by comparing the figures of the table that the nitrogen of
the intake and the total nitrogen of the output were not far apart.
In other words, there was a close approach to what the physiologist
calls nitrogenous equilibrium. In fact, it will be noted that on
several days the nitrogen output was slightly less than the nitrogen
taken in. We are, therefore, apparently justified in saying that the
above diet, simple though it was in variety, and in quantity far below
the usually accepted requirement, was quite adequate for the needs
of the body. In this connection it may be asked, what were the needs
of the body during this seven days' period? This is obviously a very
important point. Can a man on such a diet, even though it suffices to
keep up body-weight and apparently also physiological equilibrium,
do work to any extent? Will there be under such condition a proper
degree of fitness for physical work of any kind? In order to ascertain
this point, the subject was invited to do physical work at the Yale
University Gymnasium, and placed under the guidance of the director of
the gymnasium, Dr. William G. Anderson. The results of the observations
there made are here given, taken verbatim from Dr. Anderson’s report to
the writer.

On the 4th, 5th, 6th, and 7th of February, 1903, I gave to Mr. Horace
Fletcher the same kind of exercises we give to the Varsity Crew. They
are drastic and fatiguing and cannot be done by beginners without
soreness and pain resulting. The exercises he was asked to take were
of a character to tax the heart and lungs, as well as to try the
muscles of the limbs and trunk. I should not give these exercises to
Freshmen on account of their severity.

Mr. Fletcher has taken these movements with an ease that is unlooked
for. He gives evidence of no soreness or lameness, and the large
groups of muscles respond the second day without evidence of being
poisoned by Carbon dioxide. There is no evidence of distress after or
during the endurance test, _i. e._, the long run. The heart is fast
but regular. It comes back to its normal beat quicker than does the
heart of other men of his weight and age.

The case is unusual, and I am surprised that Mr. Fletcher can do
the work of trained athletes and not give marked evidences of
over-exertion. As I am in almost constant training I have gone over
the same exercises, and in about the same way, and have given the
results for a standard of comparison. [The figures are not given here.]

My conclusion, given in condensed form, is this: Mr. Fletcher performs
this work with greater ease and with fewer noticeable bad results than
any man of his age and condition I have ever worked with.

To appreciate the full significance of this report, it must be
remembered that Mr. Fletcher had for several months past taken
practically no exercise other than that involved in daily walks about
town.

In view of the strenuous work imposed during the above four days, it is
quite evident that the body had need of a certain amount of nutritive
material. Yet the work was done without apparently drawing upon any
reserve the body may have possessed. The diet, small though it was, and
with only half the accepted requirement in fuel value, still sufficed
to furnish the requisite energy. The work was accomplished with perfect
ease, without strain, without the usual resultant lameness, without
taxing the heart or lungs, and without loss of body-weight. In other
words, in Mr. Fletcher’s case at least, the body machinery was kept in
perfect fitness without the consumption of any such quantities of fuel
as has generally been considered necessary.

Just here it may be instructive to observe that the food consumed
by Mr. Fletcher during this seven days' period--and which has been
shown to be entirely adequate for his bodily needs during strenuous
activity--cost eleven cents daily, thus making the total cost for
the seven days seventy-seven cents! If we contrast this figure with
the amounts generally paid for average nourishment for a like period
of time, there is certainly food for serious thought. Mr. Fletcher
avers that he has followed his present plan of living for nearly five
years; he usually takes two meals a day; has been led to a strong
liking for sugar and carbohydrates in general and away from a meat
diet; is always in perfect health, and is constantly in a condition of
fitness for work. He practises thorough mastication, with more complete
insalivation of the food (liquid as well as solid) than is usual,
thereby insuring more complete and ready digestion and a more thorough
utilisation of the nutritive portions of the food.

In view of these results, are we not justified in asking ourselves
whether we have yet attained a clear comprehension of the real
requirements of the body in the matter of daily nutriment? Whether we
fully comprehend the best and most economical method of maintaining the
body in a state of physiological fitness? The case of Mr. Fletcher,
just described; the results noted in connection with certain Asiatic
peoples; the fruitarians and _nut_arians in our own country recently
studied by Professor Jaffa, of the University of California; all
suggest the possibility of much greater physiological economy than we
as a race are wont to practise. If these are merely exceptional cases,
we need to know it; but if, on the other hand, it is possible for
mankind in general to maintain proper nutritive conditions on dietary
standards far below those now accepted as necessary, it is time for us
to ascertain that fact. For, if our standards are now unnecessarily
high, then surely we are not only practising an uneconomical method
of sustaining life, but we are subjecting ourselves to conditions the
reverse of physiological, and which must of necessity be inimical to
our well-being. The possibility of more scientific knowledge of the
natural requirements of a healthy nutrition is made brighter by the
fact that the economic results noted in connection with our metabolism
examination of Mr. Fletcher is confirmatory of similar results
obtained under the direction and scrutiny of Sir Michael Foster at the
University of Cambridge, England, during the autumn and winter of last
year; and by Dr. Ernest Van Someren, Mr. Fletcher’s _collaborateur_,
in Venice, on subjects of various ages and of both sexes, some account
of which has already been presented to the British Medical Association
and to the International Congress of Physiologists at its last meeting
at Turin, Italy. At the same time emphasis must be laid upon the fact
that no definite and positive conclusions can be arrived at, except as
the result of careful experiments and observations on many individuals
covering long periods of time. This, however, the writer hopes to do
in the very near future, with the coöperation of a corps of interested
observers.

The problem is far-reaching. It involves not alone the individual, but
society as a whole, for beyond the individual lies the broader field
of the community, and what proves helpful for the one will eventually
react for the betterment of society, and for the improvement of mankind
in general.

INTRODUCTION TO DR. HARRY CAMPBELL’S CONTRIBUTION ON THE IMPORTANCE

OF MASTICATION

[Since the publication of Van Someren’s paper, “Was Luigi Cornaro
Right?”, read before the British Medical Association, and reprinted
elsewhere in this volume, much more attention has been given to
the study of mastication than had been previously reported. Mr.
Gladstone’s advice to his children, which was commonly current and was
repeated whenever mastication was mentioned, was usually accompanied
and met by an amused smile that showed that the full importance of
better mouth-treatment of food was not appreciated. _Glutton or
Epicure_, a little book by the present writer, published in 1898,
insisted on thorough use of the functions of the mouth in alimentation
but did not go into the anatomical, physiological and dental details.

Dr. Harry Campbell of Northwest London Hospital has performed this
latter service to science and humanity, with splendid carefulness, and
must have devoted much time and study to the collection of evidence
and suggestion which is given here following in full, reprinted from
the _London Lancet_.

The authors acknowledge with much gratitude, the courteous permission
of both Dr. Campbell and of the editor of the _Lancet_, to reprint all
four articles which composed the series.

In our own study of the subject of mouth-treatment of food we have
been led to give more credit to the chemical feature of preparation
than Dr. Campbell yet attributes to the chemical side of the problem.
Comminution of hard food is of first importance, undoubtedly, but
insalivation and neutralisation or alkalinisation are, seemingly,
much more easily and quickly accomplished in the mouth than farther
on in the alimentary canal. The intestines _can_ do all in the way
of digestion, even if the mouth and stomach are passed and their
assistance in the digestive process is entirely neglected, but it is
done at tremendous disadvantage in the supplementary digestive tract
of the intestines. We have proven the economy of letting the mouth
do _all it can_, by the insalivation (sipping and tasting) of liquids
that have taste up to the point of compulsory swallowing (a sucking-up
by the Swallowing Impulse which naturally occurs in the course of
treatment in the mouth if not fought against too strongly). If Dr.
Campbell will extend his observations to liquids, say milk, and for
a sufficiently long time to measure results by continued economy of
assimilation and saving of solid excreta, he will find that it pays
to let the mouth do all it can do, and that while it _cannot do too
much_ it _may do too little_. The natural instincts of the mouth, or
those that attach to the mouth, become much more discriminating also
if exercised on liquids as well as on solids. This they do not learn
to do so well if sapid liquids are habitually rushed past their field
of discrimination.

Taste enjoyed in the mouth is good, and a good part of the pleasure of
living comes from taste gratification, but taste that returns from the
stomach and is belched by eructation or is lingeringly reminiscent in
the mouth or nose is indicative of indigestion.

Hence it is better to dissipate taste in the mouth, which is the sole
region of taste. Spirits tasted into absorption in this way leave
no odour upon the breath, and asparagus munched and tasted to the
limit in the mouth, carries no odour to the urine. Even the stale and
disagreeable odour of onion or garlic can be neutralised by saliva and
killed in the mouth.

It is extremely difficult to get observers to practise tasting taste
out of liquids as the wine tasters do, and as the tea tasters _have to
do or die_; or, at least, become useless in their profession. Once the
efficacy of the liquid-tasting precaution in digestion is understood,
however, to swallow anything but pure water without tasting it into
absorption produces a shock. This care becomes instinctive quite
easily and regulates itself automatically. It is also a distinct gain
to the gustatory possibilities, which are very limited at best.

When the body will tolerate spirits tasted into it--not poured into
it--at all, which is not often when the nutrition is normal (only in
damp or cold weather, as a general thing, and then in the case of
the writer only at rare intervals, say two or three times a year),
the spirit will mix quickly with the saliva and become neutralised
sufficiently to excite the Swallowing Impulse. Continue sipping the
spirit for a time and you will note that there comes a point where the
saliva and the spirit do not mix, do not neutralise; the mouth becomes
unduly full of liquid without any relaxation or invitation of the
Swallowing Impulse; and the really instinctive inclination will be to
_spit it out_. It is a clear indication that the body-_toleration_ has
been fully taxed; there is no longer any bodily need for alcohol--in
fact, there is no longer natural toleration--and the secretion sent
down into the mouth is evidently mucous for a washing-out process, and
is not alkaline saliva for assisting in a utilisation function.

It is quite uncanny to observe the nicety of mouth-discrimination and
the consistency of it as related to similar substances under similar
conditions, if one learn to read it with precision and intelligence.

With increased ease of digestion, which comes with more thorough
attention to solid foods alone, the ordinary observer will think
that he has accomplished the whole of the possible benefit. It is
only when he gives sufficient time to liquids also, to get the added
delight and relief that salivary respect of them brings, that the
whole of the beneficence of mouth-service is realised. Follow this
discrimination and care to a comparative measurement of the waste of
digestion, the solid excreta, and note the increased proportionate
gain in assimilation and the value of the economy will be appreciated.
Try the different treatments on milk for a month; fifteen days with
drinking and fifteen days insalivating (sipping and tasting) the milk
to the limit, and keep account of quantity of intake required to
satisfy appetite and maintain body-weight; and also note carefully the
condition and quantity of the fæces. In the one case you will find
the waste to be _fæces_ indeed, and unmistakably worthy of the name;
but in the case of sipping, tasting and insalivating the milk to the
full satisfaction of the appetite, the _digestion-ash_ will assume
quite a different amount and character and deserve a change of name.
The proportions of the saving in our own experiments have approximated
the difference between three and ten; that is, on a reduction of only
one-third the quantity of food commonly ingested, but fully satisfying
the sipping and tasting appetite, the quantity of solid excreta was
only one-tenth of the other and of quite a different character,
æsthetically considered.

While these suggestions do not discredit or affect the value of the
purely mechanical side of the treatment as given by Dr. Campbell,
and are not intended to be controversial, they are ventured as an
amendment to be worked out in regard to liquids, which are, in fact,
only an extreme of the pultaceous foods against which Dr. Campbell
warns us as being subtly dangerous.

There is another point in our experiences and observations of the
largest importance that may appropriately be introduced here: The
treatment of all liquids in the manner suggested prevents intemperance
of drinking as effectively as it does intemperance of eating.

When food is filtered into the body after having become liquified
and made alkaline, or, at least neutral, by saliva, the appetite is
given a chance to measure the needs of the body and to discriminate
against excess. As soon as the point of complete saturation of any one
deficiency is reached, the appetite is cut off, as short as possible
to imagine, with no indication of stomach fullness. It will welcome
a little of proteid in beans, cheese, eggs, or in some other of its
richer forms, and then turn to sugar or fat in some of their numerous
forms. Thirst for water will assert itself for a moment, sometimes
asking but for a drop and again for a full glass, and afterwards, when
near the point of complete saturation, appetite will hesitate for a
moment, as if searching around for some rare substance, and may find
its final satisfaction in a single spoonful of a sweet or a sip of
something in sight.

The appetite satisfied by the infiltering process is a sweetly
appeased appetite, calm, rested, contented, normal. There is no danger
from the flooding of intemperance, for there is not even toleration
of excess either of more food or of more drink, and this contented
appetite will remain in the condition of contentment until another
need has really been earned by evaporation or destructive katabolism.

In the teaching of this physiology and psychology of alimentation to
the children of England, lies the only true solution of the drink
question, which is now the curse of the nation.

Dr. Campbell has made such a splendid case for the mechanical side
of mouth work, that it is the hope of the writer that he will give
equally careful consideration to the chemical and psychological
sides, and in a completeness of observation render inestimable service
to his country, to science, and humanity. A decade of trial on the
inmates of an infant orphan asylum will show the possibilities for the
nation in a single generation, if broadly applied. It might lead to
an effective intemperance, inhibition, or quarantine, and that is all
any nation needs of advantage to make it independent of the world and
truly great.—HORACE FLETCHER.]

OBSERVATIONS ON MASTICATION

BY HARRY CAMPBELL, M.D., F.R.C.P. (Lond.)

_Physician to the Northwest London Hospital_

[London _Lancet_, July 11, 18, 25, and August 8, 1903]

SECTION I. From _London Lancet_, July 11, 1903

THE EFFECTS OF MASTICATION

The primary object of mastication is to break up the food so as (1)
to facilitate the swallowing of it, and (2), still more important,
to insure its intimate admixture with the digestive juices, not
only within the mouth, but throughout the entire digestive tract.
Mastication has, however, other important and far-reaching effects.
Thus it promotes the flow of saliva and, when properly performed,
secures a due insalivation of the food; it increases the quantity of
alkaline saliva passing into the stomach; it stimulates the heart and
circulation; and it finally influences the nutrition of the jaws and
their appendages by stimulating the local blood and lymph circulation.
Now to consider these various objects and effects of mastication.

_Mastication facilitates swallowing._--Many foods cannot be swallowed
without first going through some preparation in the mouth. Soft, moist,
pultaceous foods, such as milk pudding and porridge, can be and often,
indeed, are swallowed with little or no preliminary chewing. On the
other hand, it is a mechanical impossibility to swallow large lumps
of tough food, or very dry food, even though, like flour, it be in a
finely divided state. Dry food needs first to be well moistened; and
it is not surprising that it promotes a more abundant flow of saliva
than moist food, though the secretion thus excited may be poor in
ferment. Hence it follows that if we desire to give foods which compel
mastication, they should be tough or dry. On the whole, vegetable foods
necessitate more thorough mastication than animal. The carnivora can
scarcely be said to masticate at all the flesh which they consume; they
simply tear off portions, and forthwith swallow them whole. Cooked
flesh, however, does require mastication, owing to the coagulation of
its proteids. The herbivora, on the other hand, unlike the carnivora,
have to subject their food to considerable mastication before it can be
swallowed; but they generally masticate it far more than is needful to
render swallowing mechanically possible, as is exemplified in the act
of rumination, the object here being to facilitate the admixture of the
digestive juices with the food.

According to Van Someren, if the habit of masticating efficiently
is once acquired, the food is not swallowed before it is converted
into the liquid state, the swallowing of unmasticated lumps being
effectually prevented by a pharyngeal reflex.

_Mastication, by breaking the food up into small particles, enables it
to be brought into intimate contact with the digestive juices._--Such
comminution is especially needful in the case of raw vegetable foods
of the tougher kind, in order to break up their cellulose framework,
and to set free the contained starch, proteids, and fats. Foods of
this kind, unless masticated, yield practically no nutriment to the
organism. I cannot too strongly emphasise the fact that before man
learned to break up the cellulose framework of his vegetable food by
cooking he was compelled to subject it to laborious mastication. But,
while thorough comminution is especially needed for vegetable food
when raw, it is also needed for many cooked forms of it also,--as, for
example, solid batter pudding and new underbaked bread, heavy lumps
of which, passing into the stomach, may seriously hamper the work of
that organ. Such substances are indigestible essentially by virtue
of their impermeability to the digestive juices, and they gain in
digestibility in proportion as they are comminuted. The indigestibility
of new bread would appear to be wholly due, not to any peculiarity
of chemical composition, but to its tendency to elude the teeth and
form a sodden mass impermeable to the digestive juices, while the more
powdery stale bread is more easily broken up both in the mouth and
within the stomach. Cabbage, again, owes its indigestibility to the
fact that it is allowed to pass into the stomach in large masses, while
the well-known digestibility of cauliflower and minced spinach is due
to the fineness of their division; were cabbage as finely minced as
spinach usually is it would be equally digestible.

Turning now to animal food it has to be remarked that while in the
raw state it may be readily digestible with little or no previous
mastication, since massive pieces of it are readily attacked by the
digestive juices, the like is much less true of animal food the
proteids of which have been coagulated and rendered less permeable by
cooking. Large lumps of hard-boiled egg or overdone meat, for instance,
may obstinately resist gastric digestion; indeed, as with vegetable
so with animal foods, their relative digestibility depends more upon
physical consistence than chemical composition; beef is generally more
indigestible than mutton and pork or veal than either, not so much
by virtue of chemical composition as of physical consistence; the
indigestibility of cheese illustrates the same truth; the individual
nutritive ingredients of this substance--the proteids and fats--are not
in themselves indigestible; casein in the form of protein or plasmon is
known to be easy of digestion, and butter is one of the most digestible
of fats; but in cheese the two are welded together into a comparatively
impermeable mass, which is apt to escape comminution by the teeth and
to pass down into the stomach in the form of solid lumps. A plain,
wholesome cheese well masticated or intimately mixed with other foods,
as in macaroni cheese, is quite easily digested by the majority.

I do not, of course, deny the influence of the chemical factor.
Undoubtedly food may disturb digestion by virtue of its chemical
composition, apart altogether from its physical characters; thus, while
cooked goose-fat sets up violent irritation in some, others cannot
tolerate eggs in any shape or form, and innumerable idiosyncrasies in
respect of special articles of diet are met with which are essentially
referable to chemical composition; but making due allowance for
this chemical influence there can, I think, be little doubt that the
digestibility of the more common articles of diet, both animal and
vegetable, depends in the main upon their physical constitution, _all
of them tending to be equally digestible when reduced to the same
degree of comminution_. This, if true, is, I need scarcely say, a fact
of the greatest practical importance, for it amounts to this: that we
may often allow to those with very weak digestions foods which are
generally considered indigestible, provided that they be thoroughly
comminuted, whether by mastication or artificial means.

_Mastication promotes the flow of saliva and the insalivation of the
food._--The more efficiently food is masticated the greater is the
salivary flow, and the more intimately is it mixed with the saliva,
or, as we say, insalivated. The saliva has apparently no effect on
fats; whether it acts on proteids seems more doubtful, though by some
authorities the penetration of these by the alkali of this fluid is
said to aid in their subsequent digestion; on starch, however, the
saliva acts very potently, and hence mastication plays a special
part in promoting the digestion of starchy foods. Indeed, if only
mastication be persisted in long enough, starch may be wholly converted
into maltose within the mouth, and it need scarcely be said that it is
better for the individual himself to manufacture his maltose in this
way than that he should take it ready made for him in the form of one
of the many “malt extracts” on the market. Patients are often forbidden
starchy food, while they are allowed the maltose which they can quite
well manufacture in their own mouths. Provided they be sufficiently
insalivated, there are few starchy foods which are indigestible, not
even excepting the proverbially indigestible new potato. These remarks
are especially applicable to children, as will be more particularly
insisted on later.

_Mastication increases the amount of alkaline saliva passing into the
stomach_, and this not only prolongs the period of starch digestion
within this organ but, by its influence upon the reaction of the
gastric contents, influences all the digestive processes taking place
there. I shall have occasion to point out later that a deficient supply
of alkaline saliva in the stomach predisposes to certain forms of
indigestion.

_Mastication acts reflexly upon the stomach._--It is now known that
the act of mastication influences the stomach reflexly, promoting the
flow of gastric juice and thus preparing the stomach for the entrance
of food into it. If the œsophagus of a dog is cut so as to allow the
swallowed food to escape instead of passing into the stomach, it is
found that the mastication of food causes a considerable flow of
gastric juice. Food introduced into the stomach unaccompanied by
mastication is less effective in promoting the gastric flow. It is
probable that the influence of mastication on the flow of gastric juice
is largely produced through the medium of psychic influences, for the
more efficient the mastication the more is the sense of taste affected.

_Mastication stimulates the heart and so promotes the general
circulation._--This stimulating action may be partly due to its local
action on the flow of blood and lymph in the jaws and accessory parts,
and partly to a reflex influence, but whatever the explanation there
can be no doubt of the fact. Hence the mere chewing of a non-nutritive
substance, such as gum arabic, is stimulating, and, doubtless, the
stimulating effects induced by the chewing of such articles as tobacco
and betel are largely to be explained in this way.

THE INFLUENCE OF MASTICATION ON THE JAWS AND ADJACENT STRUCTURES

This subject is of such importance that it needs to be dealt with in
some detail. By “adjacent structures” I mean the masticatory muscles,
tongue, teeth, salivary glands, the nasal passages and sinuses
pertaining thereto, the naso-pharynx, soft palate, and tonsils.

_The muscles of mastication._--Let me at the outset draw attention
to certain anatomical points, in connection with the muscles of
mastication. These are (_a_) their massiveness; (_b_) the very close
relation of the pterygoids to the naso-pharynx; and (_c_) the outward
direction of the pterygoids.

(_a_) It is not until one studies the muscles of mastication closely
that one comes to realise their massiveness. Their large size, in
relation to the bony structures in connection with them, is well shown
in a vertical transverse section of the head carried through the
ascending ramus of the mandible[7] (see Fig. 1). It is evident that
the functional activity of so large a mass of muscle tissue cannot but
exercise considerable influence on the nutrition of the neighbouring
parts.

[Illustration:

FIGURE 1.--Vertical transverse (slightly oblique) section through the
head on a level with the epiglottis. The massiveness of the system of
masticatory muscles is apparent.]

(_b_) The pterygoid muscles, springing as they do from the internal
pterygoid plates, must necessarily be in close relation with the
naso-pharynx, especially the internal pair, which take their origin
from the internal aspect of the internal plates. I would further
point out that the external pair, although they diverge from the
naso-pharynx on their way to the mandibular condyles, yet remain on a
level with that cavity. This close relation of the pterygoids to the
naso-pharynx is, if I mistake not, of great importance in relation to
the etiology of “adenoids.”

(_c_) Of the two pairs of pterygoids the external pair pass in the more
outward direction, forming with the sagittal plane of the head an angle
of 45° (see Figs. 1 and 2). In consequence of this direction they tend
by their contraction to pull the pterygoid plates and posterior parts
of the maxilla away from the sagittal plane of the head, and thus to
secure the normal width of the posterior nares. It is these muscles
which bring about the lateral movements of the mandible, causing the
lower teeth to move laterally and sagittally across the upper, the food
being in this way far more effectually ground than by a mere vertical
pressure of the teeth against one another. These lateral movements are,
as we shall see, less pronounced among the moderns than among primitive
peoples.

[Illustration:
FIGURE 2.--Portion of horizontal section of head about an inch below
the condyles of the lower jaw. The outward direction of the external
pterygoids is well shown; also the close relation of the levatores and
tensores palati with the internal pterygoids.]

_The influence of the contraction of the masticatory muscles on the
local circulation of blood and lymph._--When a muscle is at rest the
blood flows sluggishly through it, while there is a complete, or
all but complete, stagnation of the lymph current; if a lymphatic
trunk of a limb at rest be cut no lymph escapes from it. Rhythmic
muscle contractions, however, stimulate the flow both of blood and
lymph (_a_), in the contracting muscles themselves and (_b_) in the
neighbouring parts. (_a_) Not only are the muscle arteries dilated
during rhythmic contractions, but the blood is vigorously squirted out
of the muscle veins, so that much more blood flows through a muscle
during its rhythmic contraction than during rest. The flow of lymph is
even more markedly stimulated,--this fluid, which, while the muscle is
at rest, is stagnant or all but so, being during contraction driven
actively along the lymphatic trunks. (_b_) How greatly rhythmic muscle
contractions influence the circulation of fluids in the neighbouring
parts is shown by the flushing of the skin and the swelling of the soft
parts generally of a limb which is being exercised. We thus see how
profoundly the exercise of the masticatory muscles--and among these we
must not forget to include the tongue--influences not only their own
nutrition but that of the important structures adjacent to them--that
is to say, of the jaw-bones, salivary glands, buccal mucous membrane,
soft palate, faucial tonsils, pharynx, and naso-pharynx, as well as
of the nasal cavities and their accessory sinuses. All these parts
are during mastication copiously flushed with blood and lymph, from
which it is evident that efficient mastication must stimulate their
nutrition and favour their proper development. Hence, in one who has
from childhood upwards been accustomed to masticate efficiently, we
generally find these parts well developed, the jaws large and shapely,
the teeth regular and straight, the tongue and salivary glands large,
the nasal and naso-pharyngeal passages spacious, and the mucous
membrane of the buccal and adjoining cavities healthy.

_Influence of mastication on the jaw-bones._--It is well known that the
size of a bone is largely determined by the degree to which the muscles
attached to it are exercised. That the jaws do not grow to their normal
size, if not adequately exercised during their period of growth, is
strikingly shown by the overcrowding of the teeth, which takes place
in those brought up on soft foods, and this even though there be no
contraction of the jaws resulting from mouth-breathing. The dependence
of the size of the jaws upon the degree to which they are exercised is
also shown by the smallness of the modern jaw, as compared with that
of primitive peoples, a difference which, as we shall see, is in part
congenital and in part due to the comparative disuse of the former.
Mastication influences not only the size but also the shape of the
jaws (_a_), through its influence on the size of the tongue, which by
pressing against the teeth tends, as Sim Wallace has shown, to expand
the jaws; (_b_) by the pressure of opposing teeth against one another,
which has a similar effect; and (_c_) by the outward pull of the
pterygoids, which tends to widen the maxilla posteriorly and to broaden
the posterior nares.

_Influence of mastication on the teeth._--The teeth being developed
within the jaw-bones and remaining, even after eruption, in close
anatomical and physiological association with them, must necessarily
share in their nutritive tendencies. If these bones are efficiently
exercised during the formation of the teeth--and my remarks apply
especially to the permanent set--the tooth-germs will be abundantly
flushed with blood, while the ample growth of the jaws themselves
will provide the germs with plenty of room in which to grow and to
develop, and the more perfect their growth and development the more
resistant should we expect them to be to the ravages of caries. Who can
contemplate the jaw-bones of a six-years-old child, dissected so as to
display all the imbedded teeth, without being assured of the effect of
mastication upon dental development? Fifty-two teeth meet the view:
the whole region from the orbital rims to the inferior border of the
mandible is literally paved with them, and I can hardly doubt that
they collectively weigh more than the bone in which they are imbedded.
Surely no one can examine such a dissection without being convinced of
the urgent necessity, if the teeth are to grow and to develop normally,
of giving the child’s jaws from infancy onwards plenty of work to do.

The ample development of the jaws, which efficient mastication brings
about, has a further beneficial effect as regards the teeth, in that
it enables them to take up their proper places in the alveolar ridges,
thus securing all the advantages of a good “bite.” These I now proceed
to consider. The teeth during mastication, and especially when the bite
is good and the food of a kind necessitating vigorous and sustained
mastication, are made to move in their sockets both vertically and
horizontally; the effect of this is to stimulate the circulation in the
tooth-pulp, the alveolar periosteum (and hence also in the cementum and
alveolar walls which are supplied by it), and the circumjacent mucous
membrane of the gum. All this makes for the health of the teeth; not
only does it promote the nutrition of the tooth itself and of its bony
socket, thus maintaining a firm dental setting, but it also tends to
secure a healthy environment for the exposed part of the tooth--that
part, namely, wherein caries begins--by maintaining a healthy state of
the surrounding and, indeed, of the entire buccal mucous membrane, as
well as of the various secretions which bathe the mouth. Wherefore it
is not surprising to find that those who masticate efficiently suffer
much less from dental caries and its complications (such as abscess at
the root) and disease of the periodontal membrane (_e.g._, pyorrhœa
alveolaris and loosening of the teeth) than those who are accustomed to
bolt their food.

A few words as to the influence of mastication in wearing down the
teeth. In those races which masticate vigorously the teeth in quite
early adult life show signs of wearing away, while in later life it is
quite common for the biting surfaces to be worn flat; sometimes the
crown of the molars is worn away so that its surface shelves downwards
and inwards and not infrequently it is concave, having a scooped-out
appearance; often the dentine is exposed in this way; and yet among
many hundreds of skulls examined I do not remember to have seen one
single case where caries has started on the biting surface thus worn
down.

I had always attributed this wearing down of the teeth to the friction
of coarse food against them. Primitive races eat coarse vegetable
food, which frequently contains grit, and this doubtless helps to grind
the teeth down, but they may be markedly ground down even in those
living on soft food, and in such cases the grinding away can obviously
only be due to the friction of opposing teeth against one another.
I, indeed, believe this to be the essential cause of the phenomenon,
both in civilised races living on soft food and in primitive races
whose coarse food necessitates prolonged and vigorous mastication and
a corresponding amount of attrition between the biting surfaces of
opposing teeth. In order that this attrition may occur two things are
requisite: the upper and lower teeth must be well opposed--there must
be a good bite--and mastication must be vigorous and of the right kind.
Mere vertical pressure of the teeth against one another will not wear
away the opposing surfaces; there must be friction of these surfaces
against one another--a transverse and sagittal movement of the lower
teeth against the upper by means of the pterygoids. Mainly to this do
I attribute the marked wearing down of the teeth observed in primitive
peoples, and I am gratified to know that so competent an authority on
dental pathology as Sim Wallace is a convert to this view.

That all the teeth may be worn down just as we observe in primitive
people, even in those who have lived all their lives on the ordinary
fare of the moderns, is proved by a case I have under observation. It
is that of a man in his fiftieth year, who was brought up in Belgium
but who has resided in London for the last thirty years. When he came
to my out-patient room I was not a little surprised to find that
all his teeth were sound--a very unusual occurrence, I need hardly
say, among the London poor at his age. In seeking for an explanation
I elicited the fact that he was unable to swallow his food without
chewing it very thoroughly, and on giving him a moderate-sized piece
of bread, with the request that he should chew it in the ordinary way,
I found that he subjected it to one hundred and twenty separate bites
before swallowing it, and in the steady, deliberate way he went to work
and in his extensive lateral movements of the mandible he reminded one
for all the world of a cow chewing its cud. The temporals and masseters
of this man are enormous, and the like is no doubt true of the
pterygoids; he has well-developed nasal passages, has never suffered
from nasal obstruction, while his buccal mucous membrane is unusually
healthy for one of his years and circumstances. May we not attribute
this healthy state of the mouth, teeth, and nose to the good effects
upon them of efficient chewing? Here is a man who has lived for thirty
years in London on the same kind of food as the average poor Londoner,
but instead of finding his mouth full of carious, tartar-coated teeth,
and spongy, receding, pus-exuding gums, we find thirty-two sound teeth
firmly set in healthy gums and all but devoid of tartar.

A word as to the wearing down of the teeth in the anthropoid apes.
In this respect the gorilla differs markedly from the orang and the
chimpanzee. In all the skulls of these latter which I have examined the
teeth show signs of wearing away, while I have found the teeth of the
gorilla, with the exception of the tusk-like canines, but little worn.
From this we should expect the latter animal to be mainly carnivorous,
and the orang and chimpanzee to be largely herbivorous.

SECTION II. From _London Lancet_, July 18, 1903

CHANGES WHICH THE JAWS AND TEETH OF MAN HAVE UNDERGONE DURING MAN’S
EVOLUTION FROM HIS ANTHROPOID ANCESTORS

During man’s progress upwards from the anthropoid his diet has
undergone a progressive change, and a parallel adaptation has taken
place in his jaws and teeth. Dietetically considered, we may divide
his evolutionary career into the following epochs[8]: (1) the
anthropoid stage; (2) the pre-cooking human stage; (3) the cooking
pre-agricultural stage; (4) the early agricultural stage; and (5) the
late agricultural stage.

1. _The anthropoid stage._--The diet of man’s anthropoid ancestors
was probably much the same as is that of existing anthropoid apes; it
consisted, namely, of raw vegetable and animal food, necessitating a
vigorous use of the maxillary apparatus. This latter, we may assume,
was of the type belonging to the anthropoids--_i. e._, the jaws were
massive and markedly prognathic; the denture was the same as it is in
existing man, but the teeth were larger, especially the upper canines,
which served as weapons of offence and defence; the third molars (the
wisdom teeth) were as large as the other molars and were provided with
three fangs, and there was an ample portion of alveolar ridge behind
them; there was no chin. No doubt the massiveness and the marked
prognathism, which characterised the jaws at this stage, served other
ends than that of mastication; it is obvious that projecting jaws and
teeth are much more effectual for seizing and lacerating prey than are
the orthognathic jaws of modern man.

2. _The pre-cooking human stage_ extends from the time man’s ancestors
first assumed the human form till they learned to apply fire in the
preparation of their food. During all this period the jaws and teeth
were probably used as much, or almost as much, for mastication as
during the anthropoid stage; raw animal food had to be torn from
the bones, the latter had to be crunched, while the bulk of the
raw vegetable food needed then no less than it needs now prolonged
and vigorous mastication in order to liberate the starch and other
nutritive ingredients from their undigestible cellulose envelopes.[9]
Nevertheless, the jaws and teeth underwent considerable change during
this period, for not only were they with every advance in intelligence
called less and less into requisition for purposes of offence and
defence, but the jaws, at least, became materially modified in
correlation with the expanding cranial cavity and in connection with
the assumption of the erect posture. It is, I think, rather for these
reasons than in consequence of alterations in the nature of the food
that the masticatory apparatus now gradually lost its more bestial
aspect and assumed an essentially human type, becoming towards the
close of the period much the same as may be observed among the most
primitive peoples now living.

3. _The pre-agricultural cooking period._--The characters of the
maxillary apparatus belonging to this period are still available for
study, the aboriginal Australians, the Bushmen, Negritos, and many
Esquimaux not having yet emerged from it. So far as mastication is
concerned, cooking influences vegetable far more than animal food, for
it not only softens it but by rupturing the undigestible cellulose
chambers and liberating their contents relieves mastication of one
of its essential functions. Wherefore, with the advent of cooking,
man’s jaws and teeth began to get smaller, and they have continued to
diminish in size up to the present time. No great diminution, however,
took place at first, inasmuch as the diet still continued to be largely
animal (and prior to the use of knives and forks such food had to be
torn by the teeth), while the coarse vegetable food of this date, even
when cooked, still needed laborious mastication. The chief differences
between the maxillary apparatus of this early cooking age as compared
with that of the present day are as follows: the jaws of the earlier
period--_e. g._, in the aboriginal Australian--are more massive, and
their sagittal diameter is greater, giving rise to decided prognathism,
the teeth for the most part are larger and stronger, the third molars
being nearly, if not quite, as big as the other molars, and provided
with three fangs, while there is a considerable portion of alveolar
ridge behind them. The third molars, however, show a decided tendency
to be smaller than the rest, and the alveolar ridge behind them is less
marked than in the previous period, features, I doubt not, attributable
to the influence of cooking in diminishing mastication. Dental caries
is rare and is chiefly met with in the third molars.

4. _The early agricultural age._--All the existing primitive races
which have attained to the cultivation of the soil may be regarded as
belonging to this period. Previously to it man was mainly carnivorous,
owing to the comparatively limited quantity of vegetable food
available, so long as the supply was left to nature alone; but when by
cultivation this supply was increased and, at the same time, rendered
more constant and certain, he gradually became less carnivorous and
more vegetarian in his diet. The result of agriculture, however, is
not only to increase the supply of vegetable food, but to diminish its
fibrous, cellulosic ingredients, and thus to render it more easily
masticated. Hence at this stage we find the maxillary apparatus
becoming smaller than in the previous period, although the difference
as shown--_e. g._, by the examinations of the skulls of the African
negroes and the Melanesians--is less pronounced than we might perhaps
have anticipated; prognathism is not so decided, the jaws are smaller,
also the teeth, especially the third molars, which now for the first
time show a tendency to be furnished with two instead of three fangs,
while the alveolar ridge behind them is distinctly shorter than in
the preceding period. Dental caries, hitherto rare, now becomes more
frequent.

5. _The late agricultural period._--A mid-agricultural period might be
described, but I shall take no account of it here, but pass on to a
consideration of the late agricultural period--that, namely, in which
we ourselves live. The chief characteristic of the food of this period
is its softness. Cooked animal food requires, indeed, more mastication
than raw, but the vegetable food of to-day, owing to the combined
effects of improved agriculture, and skilful milling and cooking, is so
soft as to excite comparatively little mastication. The present may,
in fact, be described as the _age of pap_. Hence the jaws and teeth
are now called upon to perform far less work than in any earlier stage
of our evolution, and there has taken place in consequence a great
diminution in their size, more especially in the size of the jaws, so
that there is now often no room for the teeth to take up their normal
positions, and there is generally a complete absence of alveolar ridge
behind the last molars. The latter are, moreover, apt to be very small
or even absent, while dental caries is alarmingly frequent.

It will thus be seen that from the period of the anthropoids to the
present time, a progressive change in the size and shape of the jaws
and teeth has been taking place, a change which is to be explained
by (1) the cessation of the need for using them for offensive and
defensive purposes; (2) the growing capacity of the cranium and the
assumption of the erect position; (3) the progressive alteration in
man’s diet; and probably also (4) considerations of beauty. The first
three factors have operated through natural selection, the last through
sexual selection, which has come into play, I would suggest, chiefly
within recent times. Probably the most pronounced change which has
taken place in the jaws during the agricultural periods has been the
suppression of prognathism which, in the woman especially, is very
unsightly, and tends to diminish the likelihood of marriage.

INSTANCES OF THE VIGOROUS USE TO WHICH THE JAWS AND TEETH ARE PUT AMONG
EXISTING PRIMITIVE PEOPLES

A study of existing primitive peoples brings forcibly home to the
mind how laboriously the jaws and teeth of our primitive ancestors
were used. I have already shown how in pre-agricultural and early
agricultural times the nature of the food compelled a sustained and
vigorous exercise of these structures, and I wish here only to refer
to a few specific and peculiar instances of laborious mastication
exercised by primitive races now or recently living.[10] Among some
of these mastication has been promoted almost to the position of an
industrial art.

_The chewing of very tough substances in order to extract therefrom
liquid or nourishment._--The recently extinct Tasmanians included
among their articles of diet a species of sea-weed which, even when
cooked, was so tough as to require long-sustained mastication in order
to extract its nutrient elements. The Indians of North California chew
kelp, which is “as tough as white leather” (_i. e._, leather dressed
with alum). “A young fellow with good teeth will masticate a piece
of it a whole day.” Again Featherman[11] tells how when the Bushmen
are short of food in the winter they steep an old dried gnu-skin in
water and, having rubbed off the hair, boil it, and proceed to gnaw the
tough morsel until their very jaws ache. The Modoc Indians are said to
munch the raw kais root all day long.[12] Among the Esquimaux it is a
universal custom to chew the raw skin of the whale, the porpoise, and
the seal for the blubber it contains, and the skin being as tough as
india-rubber, it requires, as may be imagined, a good deal of chewing.
The Lower Californians also chew deer-skin and ox-skin (Bayert). The
more southern Esquimaux, according to Nansen, preserve the stalks of
_angelica_ by steeping them in a mixture of chewed blubber and saliva.
Finally, I may refer to the habit of chewing the sugar-cane, a practice
which is prevalent among the natives in all countries where the cane
grows, and affords, it need scarcely be said, abundant exercise for the
jaws and teeth.

_Mastication in the preparation of beverages._--I find that among
widely separated aboriginal peoples chewing is resorted to in the
preparation of beverages, both intoxicating and non-intoxicating.
The Gran Chaco Indians make an intoxicating drink by chewing the
algarroba bean and then spitting into a receptacle. In other parts of
South America berries are chewed with the same object. In some of the
Pacific Islands boys and girls with good teeth are selected to chew a
root (kava), from which they then prepare a drink. In New Guinea drinks
are similarly prepared from roots. Boiled cassava root is chewed by
the Indians of Nicaragua for the same purpose. In British Guiana the
natives make a drink by adding chewed maize and saliva to sweet potato,
maize, and sugar-cane. The Indians in Honduras, after steeping cassava
cake or carbonised bread in hot water, chew a portion and mix it with
the rest.

_Mastication in the industries._--Even among moderns teeth are used
for many purposes other than mastication--_e. g._, for holding pins
and needles and for severing cotton; also in some industries--_e.
g._, among diamond workers--where it is the custom for girls to hold
the diamond between their front teeth, which in consequence get much
worn away, as I have myself seen. It is only among primitive peoples,
however, that the jaws and teeth actually play the part of implements
for use in the arts. The Australian women make lines, nets, and bags
by chewing various kinds of fibre, a process which wears down their
teeth considerably and may cause them to be tender.[13] The Esquimaux
are still more dependent upon the use of their teeth as implements,
especially in the preparation of skins for their clothing, boats, and
lines. The teeth are used to hold the skins, while the latter are
being scraped, the mouth constituting, in fact, “a third hand;” and
the front teeth of Esquimaux women are often by this means worn away
to the merest stumps.[14] The garments of the Esquimaux, even to the
boots, are made up of skins which have been laboriously chewed for this
purpose by the women “inch by inch,” till they acquire a beautiful
softness and flexibility, and are often, indeed, chewed again after
having been dried. And we are told that the women have no objection
to the task, while the children are eager to help in it on account of
the blubber the skin contains; also, that in bad times the men do not
object to join in the work. The lines for harpooning are prepared in
a similar way from the skin of the bearded seal, and in very large
quantities.[15] When we think of the quantity of skins needed for these
lines, for their dress, including boots and gloves, and for their
boats (although for the latter some skins are used without having
first undergone chewing), it is clear that enormous quantities must be
chewed. The Esquimaux men also use their teeth considerably in other
work--_e. g._, in lashing the sledges together.[16] The Indians of
North California use their teeth for stripping the bark from the fresh
shoots employed in making their wickerwork utensils, and they also
employ their teeth in making strings, cords, and nets.

THE INSTINCT TO MASTICATE

Seeing that the maxillary apparatus of man has for long ages past been
put to vigorous use, it is not surprising that the need to exercise it
should express itself as a powerful instinct. This instinct manifests
itself in many and curious ways, some of which I will now consider.
During the early months of life the natural function of feeding at
the breast provides the infant’s jaws, tongue, and lips with all the
needful exercise. This bottle-feeding fails to do, and we frequently
find bottle-fed children seeking to satisfy the natural instinct by
sucking their thumb, fingers, or any convenient object to hand. The
teeth are a provision for biting hard foods, but even before they
actually appear we find the child seeking to exercise his toothless
gums on any hard substance he can lay hold of, and there can be no
doubt that exercise of this kind tends to facilitate the eruption of
the teeth, a truth, indeed, recognised universally, whether by the
primitive mother who strings the tooth of some wild animal round the
neck of her infant, or the up-to-date parent who provides her child
with a bejewelled ivory or coral bauble. When the teeth have erupted,
the masticatory instinct finds among primitive peoples abundant
satisfaction in the chewing of the coarse, hard foods which constitute
their dietary; but among us moderns, subsisting as we do mainly on soft
foods, affording but little exercise for the masticatory apparatus,
it does not find its proper expression, and thus tends to die out.
Nevertheless, it dies a hard death, and long continues to assert
itself; witness the tendency of children to bite their pencils and
pen-holders; I have known a child to gnaw through a bone pen-holder,
much in the same way as a carnivorous animal gnaws at a bone.

This instinct to chew for chewing’s sake manifests itself all over
the world. In our own country not only do children bite pencils and
pen-holders, but they will chew small pieces of india-rubber for hours
together. The practice of gum-chewing, so common among our American
cousins, evidently comes down from far-off times, for the primitive
Australians chew several kinds of gum, attributing to them nutrient
qualities,[17] and the Patagonians are said to keep their teeth white
and clean by chewing _matri_, a gum which exudes from the incense bush,
and is carefully collected by the women and children.[18]

A widespread custom in the East is betel-chewing, which is met with in
India, Malay, Melanesia, and Polynesia, and even among the primitive
Veddahs of Ceylon. This article is composed of the pungent leaf of
the betel plant, the areca nut and lime rolled together, and when
chewed yields a reddish juice which stains the mouth and teeth. The
Veddahs, failing to get the genuine article, manufacture a quid from
the leaves of an aromatic plant, the barks of one or two kinds of tree,
and calcined small shells.[19] The compound must possess some strange
attraction, for otherwise such pains would not be taken to secure it.
What is the attraction? Doubtless betel has stimulating properties,
and it must, moreover, be remembered that the mere mechanical act
of mastication stimulates the circulation, a fact which helps to
explain the tendency for man, all the world over, to chew non-nutrient
substances. Tobacco-chewing is common in many parts of the world, and
here, again, the effect for the time is stimulating. Pitcherie is
extensively chewed among the aboriginal Australians; it consists of
twigs of about the thickness of rye-grass stems, which are first chewed
into a mass, then mixed with the ash of gum trees, and made into a
paste, which is chewed for its stimulating and narcotic effects.[20]

I may allude in passing to the grinding of the teeth, which takes
place during sleep in disturbed states of the nervous system. It is
a true masticatory act, in which the normal lateral movement of the
mandible is well marked, and it may thus be regarded as a perverted
manifestation of the masticatory instinct.

THE CAUSATION OF INEFFICIENT MASTICATION

The effects for good upon the organism of efficient mastication being
profound and far-reaching, it follows that inefficient mastication must
lead to many evils. What these are we have now to consider; but first
it will be well to inquire into the causes of the defective mastication
which prevails among moderns.

1. _Softness of food._--By far the most important of these lies
in the nature of the food taken. The food of to-day--of the late
agricultural age period, as I have termed it--is for the most part
soft and pappy, of a kind which does not compel thorough mastication;
so much so, indeed, that, as I have already said, we may speak of this
as the age of pap. This feature is especially noticeable in the case
of children’s diet: under the modern system children are kept on a
liquid, or semi-liquid, diet, not merely during the first months, but
during the first years of life, and at the seventh or eighth month all
kinds of artificial saccharide foods in liquid or semi-liquid form are
poured into the child’s stomach; thereafter he is fed on such viands
as mashed potatoes and gravy, rusks soaked in milk, milk puddings,
bread dipped in bacon fat, pounded mutton, thin bread-and-butter,
and the like; and we are told that this is the kind of diet best
suited to the young human, from the time of weaning to the end of the
second year! The same pernicious methods are adopted subsequently.
“Perhaps the great majority of children after they have got their
complete set of temporary teeth have,” writes Dr. Sim Wallace,[21]
“a dietary such as the following. Breakfast: bread-and-milk or
porridge, milk, tea, coffee, or cocoa, bread-and-butter, perhaps an
egg. Dinner: potatoes and gravy, or meat, milk pudding. Tea: milk
or tea with bread-and-butter, jam, cakes. Supper: bread or biscuit
and milk.” Now food of this kind does not invite mastication, and it
finds its way into the stomach all too readily. Hence the instinct to
masticate has little opportunity of exercise and, not being properly
exercised, tends, as I have said, to die out. Small wonder that the
child nourished on such pappy food acquires the habit of bolting
it, and learns to reject hard, coarse foods in favour of the softer
kinds; everything nowadays must be tender, pultaceous, or “short.”
Given a choice between a food compelling little or no mastication
and one necessitating prolonged mastication--as between, say, fresh
Vienna bread and an Abernethy biscuit--and in nineteen cases out of
twenty the one which gives the least trouble in eating will be chosen.
To such absurd lengths has this harmful custom been pushed that
even bread crust is avoided by many. Witness the fashion of eating
bread-and-butter with a minimum of crust; order bread-and-butter at
any place of refreshment, and the last thing you will be served with
is a plateful of crusts of bread. Many establishments, indeed, make
a regular practice of giving away their crusts as unsaleable. Thus,
the rectangular loaves used for bread-and-butter in the “Aërated
bread-shops” are cut transversely into slices, each loaf thus yielding
two end crusts which are put into baskets for the poor, only the soft
crumby pieces being reserved for the customers, to be, in due course,
no doubt washed down by copious libations of tea and coffee.

When we trace the diet of the modern from childhood upwards we find the
same story: it tends to remain soft and pappy to the end. Animal food,
especially as it comes to the tables of the well-to-do, necessitates
very little mastication. It is the coarser varieties of vegetable food
alone which call out the full functional activity of the masticatory
apparatus, but the vegetable food of to-day is rarely of a kind to do
this; cooked vegetables, such as potatoes, greens, peas, and beans,
can be, and generally are, swallowed after little or no preliminary
mastication, and our flour is so carefully deprived of its fibrous
portions and so cunningly dealt with in the bakehouse and kitchen in
the making of bread, cakes, and pastry which shall eat light and short
that these articles get very little chewing; while such vegetable
products as rice, vermicelli, tapioca, and macaroni are, as served at
table, so soft that they slip down into the stomach almost as readily
as simple milk. Let any one run through his dietary of any one day,
and he will realise how very little work his masticatory apparatus is
called upon to perform. It will read something like the following.
Breakfast: porridge and milk, eggs, bacon, bread, and marmalade. Lunch:
fish, tender meat, boiled vegetables, bread, some “sweet,” and cheese.
Tea: bread, butter, and cake. Dinner: much the same as lunch. What
opportunity, I ask, does such a bill-of-fare afford for the development
of teeth and jaws, and for the proper functional activity of the
salivary glands?

2. _Defective masticatory apparatus._--Another potent cause of
inefficient mastication is some defect in the masticatory apparatus,
and defects of this kind are very common in those who have not been
accustomed to masticate thoroughly in early life. Foremost among these
are irregularities of the teeth leading to faulty “bite” and caries of
the teeth which causes them to be tender or to break away, if it does
not lead to their actual extraction. Mastication cannot be thorough
where the bite is defective, for this not only leads to imperfect
opposition of the upper and lower teeth, but renders the lower ones
incapable of that ample lateral movement, against the upper which is
needful to normal mastication.

3. _Idiosyncrasy._--Some are temperamentally more disposed to hurry
over their meals than others. The katabolic, restless, nervous
individual is more apt to swallow his food hastily than is his more
deliberate and phlegmatic brother. Individual differences in this
respect are even observed among the lower animals. Thus, one of a pair
of horses of about the same age and build is nervous and excitable
and inclined to bolt its food, while its companion of more stolid
temperament is a thorough and efficient masticator. The former shows
comparatively little wearing down of the teeth, and often suffers
from indigestion, a large portion of corn grains passing through
his digestive canal intact; in the latter the teeth are well worn,
indigestion never occurs, and but very few grains pass through the
digestive tract unchanged. It may be objected here that we cannot
help temperament, and to a large extent this is true; but much can be
done towards modifying it, and it is something to know where dangers,
temperamental dangers, among others, lie.

4. _Circumstances of life._--Again, in this hurrying, strenuous age
people are much less deliberate than in the easy, slow-going days of
long ago. A meal is too often regarded as something to be got through
quickly, as taking up time which might be devoted to something more
profitable. Especially is this true of breakfast and lunch; it is no
uncommon thing for a business man to hurry through his breakfast in a
few minutes, preparatory to rushing off to his train, and his lunch
as likely as not is as hastily swallowed in his office or at a bar.
Tradesmen are apt to take their meals in mere snatches; apprentices,
shop girls, and other “hands” are often not allowed sufficient time
for their meals; while, to come to the professions, we all know how
the busy medical man, for instance, is often obliged to take a hurried
snack in the short intervals between seeing his patients. No wonder
that thus circumstanced people acquire the habit of bolting their food.
A meal should be regarded as an end, and an important end, in itself.
It should be taken at leisure, body and mind being, for the time being,
given up to it, and to agreeable social intercourse. If this rule were
always observed a most important source of inefficient mastication
would be removed.

SECTION III. From _London Lancet_, July 25, 1903

EVILS RESULTING FROM INEFFICIENT MASTICATION

_Too much food is eaten._--Inefficient mastication conduces to
excessive eating. Now it is obvious that soft foods, and these
constitute the bulk of our modern dietary, pass much more readily into
the stomach than coarse, hard foods which compel a certain amount of
preliminary mastication, and for this reason the former predispose to
excessive eating: hence a danger at all periods of life, not only in
grown-ups but in children, even infants; brought up as the latter are,
mainly on liquid and pappy foods, many of them consume not only far
more than is needful, but far more than is healthful, their stomachs
being literally deluged with nutriment.

When the food is of a kind necessitating abundant mastication it is
much less likely to be taken in excess, for the longer the time spent
in mastication the less will the individual be tempted to consume;
even in the case of soft food, less will probably be eaten if it be
thoroughly masticated and insalivated than if it be bolted. Thorough
mastication, however, not only tends to diminish the amount of food
consumed on account of the time and labour which it entails; it
actually reduces the amount needful to constitute a sufficiency, for
the more perfectly the food is chewed the more perfectly is it digested
and the more economically is it disposed of in the system; the less,
moreover, is the tendency to that morbid craving for food which is so
frequent an accompaniment of defective digestion. It is certain that
appetite and the needs of the system are sooner satisfied when food is
well masticated and digested than when it is swallowed whole.

_A mass of unmasticated food may lodge in the throat and cause fatal
suffocation._--This may seem to be a very exceptional kind of evil,
but I am informed by one whose experience makes him an authority
on the ways of the British soldier that it is by no means uncommon
for soldiers in barracks to die from this cause. Usually it is when
they are under the influence of alcohol that fatal results occur,
post-mortem examination disclosing large undigested masses of food in
the stomach. A like experience is also frequently met with in the case
of men killed by accident.

_The presence of masses of imperfectly masticated food in the stomach
may cause disturbance either mechanically or by reason of their
imperviousness to the gastric juices._--We have already seen that the
digestibility of a food is largely determined by its consistence, and
that many articles of diet, such as cheese, hard-boiled egg, cocoa-nut,
lobster, and new bread, which have the reputation of being very
indigestible, can, if finely comminuted by chewing or otherwise, be
rendered quite digestible. Such articles are indigestible essentially
by reason of their compactness; the compact lumps, but little pervious
to the gastric juice, tend to undergo abnormal chemical change in the
stomach, and may in this way cause violent local irritation, even to
the extent of setting up acute gastritis; or they may paralyse the
nerves of the stomach and check gastric secretion and movement, and
thus remain _in loco_ wholly undigested for hours or even days; or,
again, more distant nervous effects may be produced, such as frontal
headache, which may be felt almost immediately after ingestion of
the peccant substance, being of reflex rather than toxic origin,
and presumably in some cases, at least, due to the mere mechanical
irritation of the stomach. The passage of imperfectly digested food
into the bowel may still further aggravate matters. It does not seem
improbable that the habitual bolting of food, by the prolonged local
irritation to which it gives rise, may predispose to cancer of the
stomach: Napoleon was a notorious fast eater and it is well known that
he died from this disease.

While, however, the bolting of food readily sets up disturbance in
some, it must be conceded that in many it seems to cause little or no
inconvenience; especially is this the case in the young with vigorous
muscular stomachs capable of triturating the food, and thus doing duty
for the teeth. The human stomach is, indeed, a long-suffering organ,
and wonderfully tolerant of ill-treatment, sometimes almost rivalling
in its hardiness the gizzard of the bird. Nor is this surprising when
we reflect that it is, in the ordinary course of nature, constantly
exposed to the entrance of noxious substances. In this respect it
stands in marked contrast to the intestines, for not only are highly
irritant substances often vomited rather than passed onwards, but in
ordinary circumstances the gastric contents are not allowed to pass
the pylorus, until they have been duly prepared by the stomach; the
pylorus, in fact, stands guard over the entrance to the bowel and is
jealous of anything passing it which is likely to injure that canal.

And just as the pylorus protects the bowel so, in exceptional cases,
may the œsophagus protect the stomach, regurgitating, after the fashion
of the ruminants, insufficiently masticated bits of food, in order
that they may be re-masticated. I have myself met with cases in point.
Sometimes, in cases of this kind, the œsophagus may be dilated into a
sort of proventriculus, which is capable of temporarily lodging a large
quantity of food. Such a proventriculus is said to have developed in
an apprentice who, not being allowed sufficient time for his dinner,
rapidly bolted it, to regurgitate it after working hours and to chew
the cud at leisure. Whether in these cases the food is ever returned
from the stomach itself I am unable to say.

While the stomach is the organ especially liable to be injured by the
swallowing of lumps of unmasticated food, the bowel may also suffer,
especially the cæcum and vermiform appendix. And here we come to one of
the most serious indictments against the bolting of food; though man
has doubtless always suffered from appendicitis, there can be little
doubt that this malady is more common now than it used to be; and
there is equally little doubt, in my own mind at least, that the cause
of its greater frequency is related to his food. I do not propose to
discuss here in detail how food is capable of causing appendicitis,
but will merely refer to one of the ways in which it may do so. I had
already come to the conclusion that the habit of bolting food is a
potent cause, when I read Sir Frederick Treves’s Cavendish Lecture in
which he makes that contention. Sir Frederick Treves points out that
in this rushing age people, especially business men, are apt to hurry
over their meals and to take them at irregular times and often while
standing at a bar; even when there is more leisure, food is rarely
masticated nowadays in the same thorough way that it was in the old
time, when it was of a coarser nature: hence solid lumps, especially
in the case of such articles as pine-apple, preserved ginger, nuts,
tough meat, and lobster, are apt to pass beyond the pylorus and,
escaping intestinal digestion, to lodge in the cæcum and precipitate an
attack of appendicitis, the most common predisposing cause of which is
a loaded cæcum, often preceded by constipation. Sir Frederick Treves
contends that this distended state of the cæcum encourages catarrh of
the appendix by dragging upon it and blocking its orifice, as well as
by twisting it and thus interfering with its blood-supply.[22]

_An excess of starch is apt to pass into the stomach._--We have just
seen that inefficient mastication tends to promote over-eating, and
what has been said on this head applies to all kinds of food, starchy
foods among others. It leads, however, to a further evil as regards
these latter; not only does it tend unduly to increase the quantity of
them consumed, but it too often causes the stomach and intestines to
become flooded with starch in a wholly undigested form. I cannot too
frequently repeat that in ancient times, especially in the pre-cooking
age, laborious mastication was needed in the case of all starchy
foods, partly because they were coarse and fibrous, but chiefly because
the starch and other nutritive ingredients had, in order to become
available for nutrition, to be liberated from their undigestible
cellulose envelopes. In these days of prepared, soft, starchy foods,
however, mastication is very little required for these purposes, but in
other respects it is as needful as ever, indeed more needful, if the
large quantities of starch which are now consumed are to be insalivated
effectually. The laborious and sustained mastication to which primitive
man was compelled to subject _his limited supplies of uncooked starchy
food, went far to effect complete digestion of the starch within the
mouth_, for raw starch is freely digested by the saliva,[23] and hence
in his case _very little passed into the stomach in a wholly undigested
form_. How different is the case with us moderns. Since the opening
of the era of agriculture and cooking, man has enormously multiplied
his supplies of saccharide, and he now consumes large quantities of
starch which has been freed from its cellulose framework by cooking,
milling, grinding, and the like, and reduced to a soft or pappy form,
such as milk puddings, porridge, boiled potatoes, and new bread, all
of which can be swallowed with little or no preliminary chewing; and
when food can be swallowed easily, without mastication, few will take
the trouble to masticate it. In these circumstances the starch does not
undergo adequate salivary digestion, and a large quantity passes wholly
undigested into, and out of, the stomach, not beginning to be digested
until it reaches the bowel. Small wonder that the latter should rebel
again this invasion and that flatulence, pain, and other dyspeptic
evils should result.

It is especially in young children that these evils are observed. Too
often the stomach of the child, semi-carnivorous, remember, by its
ancestry, is literally deluged with pure starch. At the seventh or
eighth month, or even earlier, for many of the patent infant foods
contain it, this substance is poured into the stomach without being
afforded any opportunity of undergoing salivary digestion; and for a
long time after infancy large quantities are given in the liquid or
pultaceous form, such as rusks soaked in milk, puddings, and mashed
potatoes. This practice of deluging the digestive organs with starch,
besides leading to the more immediate troubles connected with flatulent
dyspepsia, gives rise to abundant formation of toxins which, by
irritating the alimentary mucous membrane, set up gastro-intestinal
catarrh; this, again, intensifies the dyspepsia already existing and
causes a still further production of toxins, so that the motions
become intensely fœtid. These poisons being absorbed into the blood
the tissues become saturated with them and the nutrition of the entire
organism is disturbed, the faulty metabolism manifesting itself by a
diminished resistance to pathogenic agencies, by a tendency on the part
of the tissues to inflame (as shown by a liability in children thus fed
to bronchitis, rhinitis, naso-pharyngitis, and tonsillitis), by their
proneness to tuberculosis, and finally by a disposition to rickets,
which I little doubt is essentially of toxæmic origin.

Besides the above-mentioned troubles an excess of starch in the stomach
may set up hyperchlorhydria--_i. e._, that form of dyspepsia in which
there is excessive secretion of hydrochloric acid. This affection
occurs during the most vigorous years of life and is apparently due
to excessive activity on the part of the gastric glands. The excess
of acid does not give rise to any symptoms so long as there is any
unsatisfied proteid in the stomach to unite with it, but directly all
the proteid is satisfied and free acid is present in the stomach, pain,
heartburn, and distention are apt to be felt; hence these symptoms
are generally removed temporarily by a meal, the food ingested seizing
upon the free acid, and tend to recur in the course of an hour or
two. Other symptoms are mental and bodily lassitude and great mental
depression, while, if the condition is long-continued, gastric catarrh
and dilatation ensue. Eructation of the acrid mass, its removal with a
tube, or its dilution or neutralisation by an alkali, causes relief of
the symptoms. Now Dr. William Russell, who has recently studied this
form of dyspepsia, has shown, and the fact is most significant from
our present point of view, that in it starch is the last constituent
to leave the stomach; that when this organ has so far emptied itself
as to contain but one or two ounces of very acrid material the
residue consists chiefly of finely divided undigested starch, which
continues to stimulate the gastric secretion; “and, there being no more
proteid with which to combine, the secretion accumulates and leads to
hyperacidity.”[24] Inasmuch, then, as inefficient mastication leads to
an excess of starch in the stomach, we see how it may predispose to
hyperchlorhydria and we shall presently see that there is yet another
reason why it should do so.

It will be gathered from the foregoing that thorough mastication is
the most effective way of securing efficient starch digestion. This
simple fact has been most strangely overlooked. Thus “van Valzah
considers that not a little of the difficulty of the digestion of
starches and cereals can be overcome by more thorough cooking. Patients
who cannot eat potatoes after ordinary cooking are [he urges] often
able to digest them very readily if they are doubly cooked before
being served. Cereals, as a rule, should [he contends] be allowed to
simmer all night and then be thoroughly cooked for a half hour in the
morning before being eaten.”[25] This is an admirable illustration of
the modern tendency to cheat the mouth of its proper work. A much more
rational way of facilitating starch digestion in those who experience a
difficulty in this respect is by efficient mastication.

_Evils resulting from an insufficient quantity of alkali in the
stomach._--I doubt if it is adequately realised what a large amount
of alkaline saliva passes into the stomach as the result of prolonged
mastication. Its presence there serves the useful purpose of prolonging
the period of starch digestion within the stomach, while it further
aids gastric digestion not only by exciting the secretion of gastric
juice, but also by its influence on the reaction of the gastric
contents; it can scarcely be doubted that the effect is on the
whole one favourable to digestion in general. We have just seen that
defective mastication may predispose to hyperchlorhydria by allowing an
excess of pure starch to pass into the stomach, and I suggest that it
may further operate in the same direction by cheating the stomach of
its due supply of alkaline saliva. Now the saliva in this affection is
apt, as was pointed out by Sir William Roberts, to be superalkaline,
and for this reason he recommended his acid-dyspeptics to excite the
flow of it by chewing gum-mastic with the object of neutralising the
gastric hyperacidity. That relief can thus be obtained there can be no
doubt; but it is surely more rational to get the patient to stimulate
his salivary glands by masticating actual food, by which we secure
the additional advantages accruing from its complete insalivation and
comminution as well as from the reflex gastric effects. Actuated by
these considerations, I have long been in the habit of recommending
hyperchlorhydriacs to subject their food to prolonged mastication, this
being, in my belief, the most rational and effective way of breaking
the stomach of its vicious habit. In extreme cases we must insist that
each morsel of food should be chewed at least one hundred times and not
permit any relaxation of this severe discipline, until the stomach has
been schooled into healthier ways. _Evils in connection with the jaws
and their appendages and the adjacent structures: the nasal passages,
naso-pharynx, and faucial tonsils._--In those who do not masticate
properly in early life these parts fail to develop as they should,
and they are on this account alone predisposed to disease; their
resistance to disease is still further lowered by the fact of their
blood and lymph flow not being adequately stimulated by the vigorous
exercise of the masticatory muscles. Now we have seen that the great
cause of defective mastication in children is the softness of the food
given them and that the feeding of them upon an excess of soft food,
especially the starchy kind, disturbs digestion, induces toxæmia, and
in this way evokes a catarrhal tendency. In children thus fed we have
therefore several conditions which make for disease in the parts under
consideration--defective development, sluggish circulation, and toxic
saturation. Is it any wonder that the modern child should be liable
to disease in these regions, that he should so frequently suffer from
rhinitis, naso-pharyngitis, tonsillitis, and from hypertrophy of the
pharyngeal tonsil (“adenoids”) and of the faucial tonsils?

It is in this way that I would explain the frequency of adenoids among
the children of civilised communities. I claim, in fact, that this
disease is largely dietetic in origin. I submit that a child whose
nasal apparatus and naso-pharynx are well-grown and habitually bathed
by a stream of pure blood and lymph, periodically accelerated by an
ample and vigorous use of the masticatory muscles, is unlikely to
contract adenoids. On the other hand, I contend that a child in whom
these parts are ill-developed and bathed by an habitually sluggish
stream of tainted blood and lymph--one, _i. e._, that is not only
poisoned, but rarely, if ever, hurried along its lazy course by due
exercise of the muscles of mastication--I submit that such a child
runs great risk of contracting the disease. The influence in setting
up adenoids of toxic saturation with its resulting catarrhal tendency
is shown by the frequency with which this affection follows upon the
rhinitis and naso-pharyngitis of measles and diphtheria, and in order
to realise how greatly the circulation of blood and lymph in the walls
of the naso-pharynx must be influenced by mastication, one has but to
remember how very closely the pterygoids are related to this region; in
exploring it for adenoids they can, indeed, often be felt to stand out
prominently.[26]

This, then, is my explanation of the truly fearful prevalence of
adenoids among the moderns. It is essentially a disease of pap-fed
peoples. A child may, with the one exception that he is fed on a pappy,
super-saccharide diet, be brought up under ideal health conditions. He
may live in the heart of a dry, open country, far from the darkness,
dust, and tainted atmosphere of the town, sleep with the windows open
all night, live out of doors all day, be fed on the most nourishing
(too nourishing, it may be) food, be clothed after the most approved
methods, and yet, in spite of all this, we may find his naso-pharynx
packed with adenoids. This disease is, in fact, scarcely less prevalent
in the country than in the towns, scarcely less common among the rich
than among the poor. Yet in primitive communities it is practically
unknown. And what, I would ask, is the one condition in the material
environment of my supposititious child differing from that of the
primitive child? What but the factor of diet? Therefore, I say, the
prevalence of adenoids among moderns must be the result of the modern
system of feeding children, and the defective mastication which goes
along with it.

That the foregoing is a grave indictment against that system, it
need scarcely be said. For adenoid disease is fraught with many
evils, among them mental hebetude, blocking of the Eustachian tubes,
and manifold other auditory troubles, gastro-intestinal disturbances
from the passage into the stomach of unhealthy discharges, and, most
serious of all, nasal obstruction and consequent mouth-breathing.
So serious are the evils connected with this latter habit that they
demand more than a passing reference. Pronounced adenoid disease is
always associated with mouth-breathing, and there can be no doubt that
in the majority of these cases, the nasal obstruction is not in the
nasal passages primarily, but is due to a blockage of the posterior
nares by the adenoid growths, for it generally happens that nasal
breathing is rapidly re-established after their removal, though in a
certain proportion of cases the obstruction still persists, and has to
be dealt with by treatment directed to the nasal passages themselves.
Some have, indeed, contended that a primary nasal obstruction is one
important factor in the induction of adenoids, leading as it does to a
dry-cupping of the naso-pharynx during inspiration and to a consequent
congestion of its lining membrane. I am quite ready to allow that this
mechanism may play some part in causation, and such an assumption is
in entire harmony with my main contention that adenoid disease is of
dietetic origin, for nasal obstruction in children, other than that
caused by adenoids, is mainly due to defective development of the nasal
passages coupled with inflammation of their lining membrane, both of
which conditions may, as we have seen, be essentially the outcome of
defective diet.

Coming now to the evils resulting from mouth-breathing, we have first
to remember that normally the air is inhaled through the nose, and
is thus warmed, moistened, and filtered before being allowed to pass
into the lungs; but in the mouth-breather the air, which may be dry,
cold, and dust-laden, passes at once unprepared through the mouth into
the lungs, impinging in its passage against the pharynx, thus drying
and mechanically irritating the mouth, pharynx, larynx, and bronchial
tubes, all of which are thereby predisposed to disease. In this way
laryngitis and bronchitis, nay, even phthisis, may be induced. Dental
caries is also predisposed to by the habit of breathing through the
mouth. Mouth-breathing further interferes with the proper development
of the cranial bones, but especially of the maxilla, giving rise to
what may be termed the “mouth-breather’s jaw,” so characteristic is
it I do not propose to discuss here the mechanism by which this
deformity is produced, interesting though the question is; suffice it
to say that nasal breathing is essential to the normal development of
the jaws. The deformity in question, though it involves the maxilla
chiefly, affects also the mandible from the fact of its being, to a
large extent, moulded on the maxilla; in typical cases the maxilla is
small and its alveolar ridge does not attain its normal length, but is
compressed laterally towards the sagittal plane, giving rise to the
false appearance of a “high arch” and often thrusting the anterior
portion of the ridge forwards; the teeth, the growth of which is not so
much interfered with as that of the imbedding bone, are thus prevented
from taking up their proper positions and show irregularity, sometimes
extreme. Dental irregularity may also, as we shall see, result from
inadequate use of the jaws in mastication, but not to the extent which
is frequently observed in the mouth-breather’s jaws, and therefore
pronounced dental irregularity always shows that there has been
protracted nasal obstruction, and this in the vast majority of cases
implies the existence of adenoids, past or present; I say in the “vast
majority,” for in a few rare cases long-continued nasal obstruction in
children originates primarily in the nose and may lead to the typical
mouth-breather’s jaw, with the resulting dental irregularity.

_The tongue._--If the tongue is not properly exercised in childhood
and youth, we find it imperfectly developed; hence in inefficient
masticators it is generally small. It must not be forgotten in this
connection that this organ is considerably exercised when the infant
is at the breast, from which the milk is obtained, not by suction,
but by a vigorous tugging and squeezing of the nipple (in which the
tongue takes considerable part), whereby the gland is reflexly excited
to secrete. When, on the other hand, the child feeds at the bottle he
obtains his milk by actual suction, and generally through an orifice
of such ample dimensions as to allow the bottle to be rapidly emptied
with comparatively little exercise of the lips and tongue. In short,
the breast-fed infant has to do some work for his living, and that of a
sort calculated to promote the health of the jaws and their appendages,
while the bottle-fed child can glut himself by doing very little more
than opening his mouth; wherefore we find the tongue and adjacent parts
less developed in the latter than in the former. It may be thought to
be a matter of indifference whether the tongue develops to its normal
proportions or remains small, but such is by no means the case, for, as
Dr. J. Sim Wallace has shown, the pressure of this structure against
the teeth promotes the normal development of the jaws, especially of
the mandible, and when it is small they are apt to be so too.

_The salivary glands._--Just as mastication increases the functional
activity of the salivary glands and buccal glands and favours their
normal development, so, contrariwise, inefficient mastication during
early life fails to call forth their normal functional activity and
to secure their adequate development. Thus we find that a child who
has been brought up on hard, starchy foods, necessitating abundant
mastication has much larger and more active salivary glands than
one who has been fed on soft foods which slip down into the stomach
before they have had the chance of being properly masticated, and it
is needless to say that the more efficient these glands are the more
likely is digestion to be carried out satisfactorily.

_The jaw-bones._--If the jaws are not adequately exercised in youth
by mastication they fail to grow to their normal size and shape, and
there is apt in consequence to be overcrowding of the teeth. The main
defect of the jaws in such cases is their smallness; they do not
present that pronounced lateral compression and anterior protrusion
which characterise the mouth-breather’s jaw, nor such extreme dental
irregularity, the most common being overlapping of the incisors,
displacement of the canines, and difficulties in regard to the eruption
of the wisdom teeth from shortness of the alveolar ridge. I have
already referred to the progressive shortening in the post-molar ridge,
which has been taking place during man’s evolution from the anthropoid
in correspondence with the alteration in his diet.

We thus see that defective use of the jaws leads to irregularity of
the teeth (1) directly and (2) indirectly through the induction of
adenoids. This irregularity is not only unsightly but leads to certain
evils which thus primarily owe their origin, in large measure at least,
to defective mastication. What, then, are these evils? In the first
place, dental irregularity predisposes to dental caries by favouring
the lodgement of food between the teeth; in the next place, it leads to
defective “bite.” Now when the bite is defective adequate mastication
is impossible, for not only is it impossible in these circumstances
to oppose the teeth properly, but also, owing to their interlocking,
to accomplish that free lateral movement of the lower teeth against
the upper, which belongs to normal mastication. I do not say that
defective bite is the sole cause of this imperfect lateral movement;
it may, indeed, be observed in most moderns brought up on soft pappy
food, whether the bite be good or not. Normal mastication is, in fact,
becoming a lost art; the average modern masticates mainly by a vertical
compression of the lower teeth against the upper, and in only a small
degree by a lateral frictional movement which, it is needless to say,
is the more effective method for grinding purposes; and it is, I doubt
not, chiefly for this reason that the teeth of modern man are so much
less worn down than those of primitive peoples.

_The teeth._--Imperfect use of the teeth leads to many ills. When
adequately exercised and made to execute for one or two hours every day
a lively dance in their sockets, during which the circulation of blood
and lymph in the tooth-pulp, periodontal membrane, and surrounding
tissue of the gum is vigorously stimulated, and the cavity of the mouth
is bathed in a copious flow of salivary and other buccal secretions, we
have conditions which make alike for the health of the buccal mucous
membrane, of the teeth, and of the periodontal membrane and alveoli;
but when the circulation is not duly stimulated in this way the teeth
do not develop properly, while the secretions of the mouth are apt to
be scanty and unhealthy, both of which conditions predispose to caries.
How far dental caries is due to inherent dental weakness and how far
to faulty conditions outside the teeth we need not stop to inquire; Dr.
Wallace attributes little influence to the former factor, contending
that caries depends essentially upon faulty dental environment; and
one can scarcely doubt that the state of the gums and of the oral
secretions profoundly influences the growth of bacteria in the mouth,
upon the acid yielded by which organisms the corrosion of the dental
enamel essentially depends. Faulty conditions of the oral secretions
likewise favour the deposit of tartar.

Another result of imperfect use of the teeth is undue thinness of
the alveolar walls and periodontal membrane, in consequence of which
the teeth are not so firmly held in their sockets as they should be.
This is, I believe, one of the reasons why they are prone to fall
out prematurely among the moderns: we know that the teeth tend to
drop out in old people owing to a senile atrophy of the alveolar
walls; the Haversian canals get smaller and may, indeed, disappear
entirely, and it stands to reason that this atrophy must be hastened by
inefficient exercise of the teeth. So far as I am able to gather from
an examination of skulls in museums, the teeth are rarely shed among
primitive peoples before extreme old age, while among moderns they
frequently fall out long ere this is attained.

A still worse evil attaching to insufficient use of the teeth is
pyorrhœa alveolaris or Riggs’s disease, which, in conjunction with the
deposit of tartar, is the great cause of the premature loosening and
shedding of the teeth observed among latter-day civilised peoples.
This affection consists of a purulent inflammation of the periodontal
membrane, owing to the invasion of it by pyogenic cocci, so that pus
wells up on pressing the gum against the teeth. Now, when by a vigorous
use of the teeth the buccal cavity is kept well flushed with healthy
secretions, the growth of micro-organisms within this chamber is kept
down, and when, by the same means, the vitality of the periodontal
membrane and adjacent tissues of the gum is periodically stimulated,
these tissues offer stout resistance to the invasion of pathogenic
organisms; but when, contrariwise, the teeth are little used, the
secretions of the mouth are in consequence defective both as to
quality and quantity, and the growth of organisms in the buccal cavity
is promoted; and when, further, the circulation in the periodontal
membrane and adjacent soft tissues is not adequately stimulated by
vigorous mastication, their vitality is poor and they offer but a
feeble resistance to parasitic invasion. We can thus, I think, safely
infer that inefficient mastication is a potent cause of pyorrhœa
alveolaris; and the chief cause of inefficient mastication being the
eating of soft foods, we must also conclude that the latter practice
is chiefly responsible for the disease in question; such foods further
predispose to this affection in that they are apt to lodge between
the teeth and by undergoing decomposition there to favour the growth
of micro-organisms within the mouth. The condition of the teeth and
gums among the civilised poor is, alas, little calculated to make us
proud of our boasted civilisation--the spongy pus-exuding gums, the
lengthening, loose, tartar-covered, carious teeth, and the putrescent
breath constitute a damning indictment against our modern system of
living on a soft, pappy diet, and not giving the teeth the work for
which they are designed. I never examine such a mouth without being
impressed with, and I may add oppressed by, this fact.

I am not, of course, contending that pyorrhœa alveolaris only occurs
in those who masticate inefficiently; whatever causes an unhealthy
condition of the gums and saliva predisposes to it, but it is surely
much less common in those who masticate well than in those who
masticate ill. Confirmatory of this statement is the fact that it is
more frequent in those with irregular teeth than in those with a good
bite, who are thus able to put their teeth to more effective use. This
affection is very common among the carnivora of menageries as well as
among dogs and cats; indeed, one seldom fails to find it in dogs over
four years of age, and in old dogs it is generally rampant. Doubtless
in all these cases the general conditions of life play some part in
the causation of the disease, but I do not think that we can eliminate
from it the factor of defective use of the jaws and teeth, for it is
certain that dogs and cats are fed largely on pappy foods and are often
insufficiently supplied with bones.

_The causation of dental caries._--Dr. Wallace, in his philosophical
work on “The Cause and Prevention of Decay in Teeth,” contends that
the cause of the prevalence of dental caries is that the natural
food-stuffs are, to a large extent, ridded of their accompanying
fibrous parts and consumed in a form which renders them liable to
lodge and to undergo acid fermentation in the mouth; while from the
same cause and the induced conditions the micro-organisms of the mouth
lodge and multiply and augment the rapidity and intensity of the acid
fermentation. I am perfectly at one with Dr. Wallace in believing
that the removal of the fibrous portions of food is the main cause of
the prevalence of caries among moderns, and I can hardly doubt that
foods so prepared tend to promote caries in the way indicated, but I
venture to think that they do this even more by failing to call forth
the normal degree of mastication. I cannot but think that if these same
soft foods were as laboriously masticated as they would need to be if
they retained their fibrous ingredients, dental caries would be much
less common than it actually is. I have endeavoured to show how very
different the local conditions are in the efficient from what they are
in the inefficient masticator--how in the former the jaws and teeth
are wont to be well developed, the bite to be good, and the secretions
which bathe the teeth to be of a kind calculated to promote their
health; and how in the latter an entirely opposite set of conditions is
wont to prevail. That it is possible to maintain a fine set of healthy
teeth till past middle life on ordinary civilised diet, provided the
food be habitually subjected to efficient mastication, is shown in the
case of the man already referred to, and by numerous other cases which
I have observed.

Since the application of cooking to food there has been a progressive
lessening in the work of the jaws and teeth and, parallel with this,
a diminution in their size and an incursion of dental caries. Among
the anthropoids in their natural state caries is practically unknown,
and I think we may conclude that the same was true of man before he
learnt to cook. In the pre-agricultural races, such as the aboriginal
Australians, the effect of cooking the food is shown in the lessening
in the size of the wisdom teeth and of the post-wisdom alveolar
ridge; dental caries, though rare among these people, does occur, and
especially in the wisdom teeth.[27] In the early agricultural period,
owing to the increasing softness of the vegetable food, the jaws and
teeth show a tendency to be smaller than in the previous periods; the
wisdom teeth are decidedly smaller and more prone to caries, while
caries of the other teeth is by no means rare. In the late agricultural
period the jaws and teeth often show very decided defects of
development, while dental caries is, as we know but too well, rampant.

What has been said concerning the relative prevalence of caries in
different diet epochs applies to many other diseases of the teeth;
thus, along with the increase of caries, there has been a parallel
increase in the prevalence of pyorrhœa alveolaris.

CONCLUDING REMARKS

I have now set forth some of the evils resulting from inefficient
mastication. They are many and serious. The immediate evils, such
as over-eating, indigestion, adenoids, dental caries, and pyorrhœa
alveolaris, are bad enough, but when we consider the secondary evils
to which these primary ones give rise,--and I have only mentioned a
few of them,--we must come to the conclusion that an appalling amount
of misery and suffering may be saved by the simple expedient of
inculcating the habit of efficient mastication. How this end can best
be accomplished will be considered in the next section.

SECTION IV. From _London Lancet_, August 8, 1903

MEANS OF INSURING ADEQUATE MASTICATION

In order to secure the full advantages accruing from the use of the
jaws and their appendages, it is, above all, necessary for them to be
adequately exercised during the period of development. If this is done,
not only will the tendency to dental caries, adenoids, indigestion,
and other evils be greatly diminished, but the masticatory instinct
will establish itself as a permanent force, so that the individual
will tend for the rest of his life to subject even soft foods to
thorough mastication. The tongue, the lips, and the jaws of the newly
born child find their natural exercise at the mother’s breast, and
we should, therefore, do our utmost to get the mother to suckle her
child, the bottle affording neither the same kind nor the same amount
of exercise. If, unhappily, we fail in this, we must see that the teat
of the feeding-bottle is so constructed as to compel the child to
earn his meal by, at any rate, some exercise. This kind of exercise
promotes the growth of the tongue and thus of the jaws, especially of
the mandible. Directly the infant shows a disposition to bite hard
things the instinct should be gratified. We may observe a tendency in
this direction as early as the third or fourth month, and it becomes
more and more pronounced when, the time for the eruption of the teeth
approaching, the gums begin to swell up and to get tender, and saliva
begins to flow from the mouth; it is now, more than ever, necessary to
provide the child with hard substances on which to exercise the jaws
and the gums, and a great deal of the trouble of teething is due to
the failure to recognise this fact. What, then, are we to employ for
this purpose? I am convinced that it is a mistake to rely solely, or
even mainly, upon baubles of ivory, coral, and the like useful though
these may be in their way; it is far better to give the child something
which is not only hard but nutrient and pleasant to the taste,
something which will at one and the same time exercise the maxillary
apparatus, excite the gustatory organs, and provide a certain amount
of nutriment. To this end we may, as the teething time approaches,
give a chop or chicken bone, from which most of the meat has been
removed; by powdering the bone with white sugar or salt we may increase
its attractiveness. From such bones a good deal of nutriment can be
extracted, and this of a kind which is most acceptable to the infant
stomach, for it must be remembered that the young human is in the
main carnivorous. Indeed, since milk is a purely animal diet, all the
mammals must be regarded as essentially carnivorous during the period
of suckling, while man, as already observed, from the time he emerged
from the anthropoid until he learned to cook his food, was throughout
life mainly an animal feeder. Therefore we should not hesitate to allow
the teething infant animal food in the form suggested. Chicken and
chop bones, yielding as they do before the pressure on the gums, are,
moreover, just of the right degree of consistence for the purpose in
view, while they afford abundant exercise for the tongue; ivory, coral,
and the like are, on the other hand, too hard and unyielding, and lack,
moreover, the attractiveness belonging to sapidity.

By thus providing the maxillary apparatus with suitable exercise we
shall do much to facilitate the eruption of the teeth and to favour the
growth of the jaws and their appendages, including the salivary glands,
and so to prepare the mouth for the reception of vegetable food. This
should, of course, not be given till the teeth appear. The order in
which these make their appearance gives some indication as to the
order in which vegetable food should be administered to the child. The
first teeth to penetrate the gums are the lower incisors which appear
from the seventh to the eighth month; then follow the upper incisors
from the seventh to the tenth month. These teeth enable the child to
_bite_, but not, be it observed, to _masticate_, for which function
the molars are necessary. Now the first molars do not appear till the
twelfth or fourteenth month; the second molars not till between the
fourteenth and the twentieth month; and it seems to me certain that
our primitive ancestors could not have obtained starch in any quantity
until they reached this age; at the best, pre-cooking man was but
scantily supplied with starch, and such slender supply as he had
could only be rendered accessible to the digestive juices by vigorous
mastication, which broke up the indigestible cellulose framework in
which all vegetable starch is contained; hence, until the young human
cut his molars, he had little opportunity of securing any starch.
These considerations strongly suggest the desirability of giving but
small quantities of starch before the twelfth month, and though the
facts, that ptyaline appears in the saliva about the time the first
incisors are cut, and that pancreatic juice develops its amylolytic
ferment at the same time, show that the digestive organs are ready for
the reception of some starch at the seventh or eighth month, yet I
believe the quantity should be strictly limited. I am ready to admit
that the modern child may have, indeed probably has, a greater power of
digesting starch than his remote pre-agricultural ancestor; but even
so, I am convinced that we should be on our guard not to over-gorge
infants with this substance. Only a small quantity should be given
before the twelfth month, and it should be gradually increased up to
the twentieth month.

I have said that the pre-agricultural infant was unable to secure
starch in any quantity by means of his incisors. These teeth enabled
him, however, to obtain some soluble nutriment from fruits, and
Dr. Sim Wallace has suggested that the early eruption of the lower
incisors is for the purpose of enabling the infant to pierce the
outer covering of fruits so as to permit him to extract the soluble
contents by suction; and, accordingly, when these teeth are cut we
may allow the child to bite at such vegetable substances as apples,
oranges, and sugar-cane. The latter is a useful article of diet for
children, for it provides soluble saccharide in a diluted form, and
it is advisable that the child should receive his cane sugar well
diluted, for it must be remembered that before the agricultural period
man’s supply of pure sugar was limited to wild honey which, consisting
as it does almost entirely of mono-saccharide (grape sugar and fruit
sugar), is very easily disposed of by the digestive organs. Nowadays,
the less digestible cane sugar (which is a di-saccharide) is very
largely consumed in the undiluted state, in which it is apt to set up
disturbance. When, however, it is obtained by chewing the sugar-cane,
it is diluted both by the water in the cane and by the saliva, and I
should like to see children obtain most of their cane sugar in this way.

The consideration of the conditions obtaining for pre-agricultural man
not only strongly suggests that the young human of to-day should be
given starch in very moderate quantities up to the twelfth month, but
it points an even more important lesson--viz., that this substance
should be given not, as is the custom, as liquid or pap, but in a form
compelling vigorous mastication, for it is certain that early man, from
the time he emerged from the ape till he discovered how to cook his
vegetable food, obtained practically all his starch in such a form;
it cannot too often be repeated that uncooked starch in the natural
state, locked up as it is in chambers of indigestible cellulose, has no
nutritive value; these chambers need first to be broken up by prolonged
and energetic chewing, and in this way much or most of the starch is
converted in the mouth into dextrines and maltose, very little passing
into the stomach in the crude state to set up disturbance in that
organ and later in the bowel. If it is given as liquid or pap it will
pass down as starch into the stomach, while if it is administered in
a form which obliges the child to chew it properly, not only will the
jaws, the teeth, and the gums obtain the exercise which they crave,
and without which they cannot develop normally, but the starch will be
so thoroughly insalivated that much of it will be converted within the
mouth into maltose. How foolish to upset the child’s digestive system
by deluging it with liquid starch, and then to endeavour to correct
matters by giving the malt extract which the child can and should
himself manufacture within the laboratory of his buccal cavity.

Clearly, then, the child should make his first acquaintance with
starch, not in the form of a liquid or pappy patent food, but in a
solid and somewhat tough form. The best means of achieving this end
is occupying my attention, and I hope soon to publish the results of
my investigation. Meanwhile, I would point out that hard, well-baked
crusts constitute a convenient form in which to administer starch to
children. A piece of crust may be put in the oven and re-baked; this
not only hardens it but helps to convert the starch into dextrine,
which is a stage on the road to maltose. If the crust be then cut
into a suitable shape and spread with bacon fat or fresh butter, it
constitutes a most agreeable morsel. Later, we may give hard plain
biscuits. The same principle should be acted upon during later
childhood and youth: we should always give, as far as possible, the
starch in a form compelling abundant mastication. Loaves should be
shaped so as to give a maximum of crust and a minimum of crumb,
and should be baked hard. Such loaves are quite as nutritious as
the ordinary ones, and much more digestible, containing as they do
an abundance of dextrine and not a little maltose, and compelling
efficient mastication, especially if eaten, as they should be, without
any fluid. A lady who has the catering for a large number of girls
gives the bread in this way, and she tells me that there is keen
competition for the most crusty portions.

I do not say that starch in the liquid and pappy form should find no
place whatever in man’s dietary at the present day, for this would
imply the prohibition of porridge, boiled potatoes, milk puddings,
and the like. We cannot put back the hand of time and return to the
food of our primitive ancestors, nor is it desirable that we should;
but we can, at least, arrange matters so that a large proportion
of the starch we consume shall be in a form inviting mastication,
such as crusts, stale bread, stale cake, biscuits, and so forth. The
less children eat of pastry, or, indeed, of any luxurious foods, the
better; if brought up on a healthy dietary and under healthy conditions
generally, they will relish their simple fare more than the choicest
dishes of the epicure. I do not, I say, object to the child consuming
a certain proportion of starch in the liquid or pultaceous form, for
if, by bringing him up on a rational dietary, his instinct to masticate
be afforded due opportunity to develop he will be likely to subject
even soft vegetable food to something like adequate mastication; this
will tend to mitigate the evils associated with such food, not only by
facilitating the digestion of starch, but by flushing the mouth and
promoting the health of the teeth and buccal mucous membrane.

The question how far children should be allowed to crack nuts may here
be considered. If the child has been brought up on pappy food, and has
in consequence brittle and ill-developed teeth, the cracking of hard
nuts will be likely to injure them, and this is _a fortiori_ true if
any of the teeth are carious or “filled.” And not only nuts but hard
food of any kind, such as ship’s biscuits, may in these circumstances
injure the teeth, as many of those who went through the recent South
African campaign can testify. But if, on the other hand, the child has
from the beginning been fed on coarse, hard foods, so that the teeth
have been allowed to grow dense and strong, no harm is likely to ensue
from cracking such nuts as filberts and Spanish nuts. If a squirrel
or a monkey weighing a few pounds can do so with impunity, surely the
young human should be able to also. The cracking should, however, be
done by the molars, while such hard nuts as Brazils had best not be
tackled at all.

Animal food does not need the same amount of mastication as vegetable
food, since it is not digested in the mouth, though some contend that
the mixture of proteid with alkaline saliva facilitates its subsequent
peptonisation. Cooked animal food is, however, all the better for some
mastication, owing to the coagulation of the proteids, and, in order
to insure the efficient mastication of meat, fish, and poultry, Dr.
Sim Wallace recommends that they should be given in large pieces cut
thin. “Flat pieces about one inch square generally _necessitate_ a
certain amount of mastication. It is difficult to swallow large flat
pieces of meat without mastication, but when finely minced little or no
mastication is called forth.” The younger the child the more underdone
should the meat be.

EXAMINATION OF THE MOUTH AND ADJACENT PARTS

If a child be brought up on the lines indicated and under healthy
conditions generally, it is tolerably certain that the maxillary
apparatus will develop normally, that the teeth will be strong and
well opposed, and show little tendency to disease; but, inasmuch as
the methods advocated are but seldom put into practice, disorders of
the teeth, more especially caries and irregularities, are common, and
hence with a view to promote more efficient mastication it is always
advisable to examine our patient’s teeth.

Each individual tooth should be inspected in a good light for the
presence of caries, and careful note should be taken of the “bite,”
a normal bite implying not only a proper opposition of the two rows
of teeth but the capacity of the lower ones to move freely across the
upper; mere vertical movement of the mandible does not constitute
efficient mastication. In this connection it must not be forgotten that
an unopposed molar is useless for purposes of mastication, and it is by
no means rare to find in a mouth several sound unopposed molars which
are for this reason absolutely functionless. Nay, more than this, it
may happen that teeth, perfectly sound ones, too, far from helping, may
actually interfere with mastication; thus, among the poor, we sometimes
find all the teeth gone save the upper canines and the lower incisors,
and the teeth and gums being alike unable to come into contact, nothing
worthy of the name of mastication is possible; it would be far better
to be without any teeth whatever, for the toothless gums would then be
permitted to come into contact along their entire extent, under which
condition they gradually harden and come to be quite efficient grinding
agents.

Next the gums, the alveoli, and the roots of the teeth must be
examined, especially for the presence of erosion, tartar, and pyorrhœa
alveolaris, this latter condition being evidenced by the welling-up of
pus upon pressing the gums against the sides of the teeth.

If our examination of the mouth discloses anything likely to interfere
with mastication the aid of the dentist should at once be sought, but
every physician should be so far acquainted with disorders of the
teeth as to be able to say, in the majority of cases, at all events,
when this is necessary. I am convinced that far more illness than is
generally supposed is attributable to dental defects, and this even
among the more leisured classes. With regard to pyorrhœa alveolaris, it
has to be remembered that it not only does harm by causing loosening,
lengthening, and shedding of the teeth, and thus interfering with
mastication, but also by contaminating the stomach and the blood and
thus upsetting the digestion and causing constitutional diseases, such
as anæmia and arthritis; and inasmuch as poisonous discharges from
the nose, the naso-pharynx, the pharynx, and the tonsils may act in a
similar way, these parts also should be inspected in connection with
the examination of the teeth. In the dust-laden atmosphere of towns
they are very liable to disease, and even when healthy are necessarily
dirtied; some go so far as to advise all town dwellers daily to wash
out the nasal passages and to gargle the throat; but, whatever may be
thought of this, it is certain that under existing dietetic conditions
special means are needed in order to keep the mouth and teeth clean.
When man fed on raw food this was not necessary, the food itself
and the copious flow of saliva, induced by prolonged mastication,
effectually cleansing these parts; but, under present conditions, food
tends to remain within the mouth, especially between the teeth and in
their crevices, and therefore special means are needed to remove it.
This is done by “cleaning the teeth” and by rinsing the mouth.

_The tooth-brush._--Probably the ideal method of cleaning the teeth
is that adopted by many primitive and not a few semi-civilised
peoples--viz., rubbing them with a twig of wood which has been teased
out at one end so as to form a sort of brush by means of which the
teeth can be burnished and food dislodged from them. The modern
tooth-brush requires to be used with great caution, as it is capable of
doing much harm, not only by removing the mucoid film, which, according
to Dr. Wallace, protects the teeth from corroding agencies,[28] but
probably also by injuring the edge of the gum and the neck of the
teeth, and thus setting up the condition known as “erosion.” Certain
it is that some of the best sets of teeth I have encountered have been
wholly unacquainted with the tooth-brush. In any case the brush should
be employed with great care; it should be soft, and should always be
drawn away from the gums both on the inner and outer aspect of the
teeth towards the biting surface, as well as across the latter, never
transversely across the outer surfaces, as so frequently is done. The
object of these procedures is to dislodge any particles of food that
may have collected between the teeth or in their crevices. For this
purpose the toothpick may also be employed judiciously. In order to
render the enamel of the teeth white it is better to rub each tooth
carefully with some soft material, such as chamois leather, rather
than to scrub them with a brush. Tooth-powders should not be used as
a matter of routine, but only occasionally and for appearance rather
than for cleanliness, and should consist of some simple non-irritant
material. Antiseptic powders and washes are to be scrupulously avoided,
for it is neither desirable nor possible to render the buccal cavity
aseptic; myriads of bacteria flourish within it, many of which play
a useful part as scavengers. The time of all others for cleaning
the teeth is just before going to bed, so that the food shall not be
allowed to decompose in the mouth during the night. There will then be
no need to use the tooth-brush in the morning.

_Rinsing the mouth._--The mouth should be rinsed out as a matter of
routine after each meal and on rising, and care should be taken to do
this before the early cup of tea, so as not to contaminate the stomach
with the buccal secretions which have accumulated during the night.
Inasmuch as raw vegetable food has a cleansing effect on the teeth, it
is often a wise plan, especially in the case of children, to finish a
meal with some kind of fruit, such as an apple or an orange. It hardly
seems necessary to insist upon the necessity for keeping all artificial
dentures thoroughly clean.

PROFESSOR PAWLOW’S DEMONSTRATIONS OF PSYCHIC INFLUENCE IN DIGESTION

[In presenting a theory of human alimentation involving mental or
nervous as well as mechanical and chemical factors which influence
it for good, it is not often that an author is able to enlist the
assistance of a complete battery of scientific confirmation to fortify
his own crude observations taken direct from personal experience in
the study of natural requirements.

Professor Pawlow, with his marvellously skilful investigation of the
workings of the digestive secretions, and Dr. Cannon of the Harvard
Medical School, by aid of persistent and patient X-ray studies,
explain how it is that earned appetite and thorough mouth-treatment
of food are preliminary necessities of easy digestion, and that
disturbance or shock of any sort during the process stop digestive
proceedings and endanger health. They show also that when the mouth is
used to do _all that it can do_ in the work of digestion all the rest
is easily accomplished by the NATURAL AUTOMATIC PROCESSES within the
body.

They both show that we have, each of us, a certain responsibility in
the matter of right digestion and healthy nutrition, and that all
this personal responsibility is located in the head, in the mind, and
in the mouth, and that while the alimentation is proceeding it is a
sacred duty to do our part _right_, according to the intelligence that
these most valuable demonstrations teach.

Professor Pawlow has allowed publication of his lectures in Russian
and German, and recently Professor W. H. Thompson of the Physiological
Department of Trinity College, Dublin, has made an English translation
which is issued by Charles Griffin & Company of London and J. B.
Lippincott of Philadelphia.

The author has to express special gratitude to Professor Pawlow,
Professor Thompson, Messrs Griffin and Lippincott for permission to
reprint herein some entire lectures and extracts that bear especially
on the practical understanding of our subject.

Professor Pawlow is one of the Board of Scientific Assessors mentioned
in the REPORT of a PLAN for an INTERNATIONAL INQUIRY into the subject
of HUMAN NUTRITION.

In one of the lectures, not here reprinted, Professor Pawlow gives
merited recognition of the early statements of the French physiologist
Blondlot relative to psychic influence on the digestive secretions
made some half century ago, but discredited by physiologists since
that time, owing to insufficiency of evidence brought forward in
support of the statements.

Professor Pawlow’s acknowledgment is so gracefully rendered that it is
here given as a model of scientific courtesy.

“I have depicted the work of the gastric glands as we have seen it
in our experiments, and as it has developed under our hands. Is the
picture a new one? In its details, yes; but not in its fundamental
features. However singular it may appear, the sketch of this
picture was more than fifty years ago outlined by physiology. May
this constitute another reason for our science relinquishing its
characteristic shyness of new things and for its conversion to our
interpretation of the phenomena under consideration!

“The talented author of the _Traité Analytique de la
Digestion_--Blondlot--spoke in plain words of the importance of taking
food, and of the specific excitability of the gastric mucous membrane.
The facts adduced in the working up of his theory were naturally
insufficient, but we must not forget that the first experiments on
dogs with artificial gastric fistulæ had only just been performed.
It is truly incomprehensible that the researches of Blondlot and his
views upon the secretion of gastric juice have experienced during the
past fifty years no completion, no additions, but, on the contrary,
have passed out of sight, thanks to the faulty experiments and
erroneous representations of later authors. Only in the works of a
few writers--and those mostly French--has Blondlot’s theory survived.
Of other investigators we must give mention to Heidenhain, who has
enriched the physiology of absorption in general, but more especially,
in connection with the secretory work of the stomach, has discovered
many important facts and has given birth to many fruitful ideas. From
him proceed the subdivision of the secretory process according to
periods and exciting agencies, as well as the suggestion that it would
be important to investigate the individual food-stuffs in relation
to the work of the stomach. Heidenhain’s results are contained in
his well-known article on the secretion of the cardiac glands of the
stomach, published in the year 1879 in PFLÜGER’S ARCHIVES. The work of
Blondlot and the additions of Heidenhain comprise almost everything
of importance which was accomplished by physiology in fifty years
concerning the conditions and mechanism of the secretory work of the
stomach during digestion. Full of moment, however, for our subject was
the obvious error that mechanical stimulation constituted an effective
excitant of the gastric glands, and this error was in its turn a
result of faulty methods.”—HORACE FLETCHER.]

LECTURE IV

GENERAL SCHEME OF AN INNERVATION MECHANISM--THE WORK OF THE NERVOUS
APPARATUS OF THE SALIVARY GLANDS--APPETITE, THE FIRST AND MOST POTENT
EXCITER OF THE GASTRIC SECRETION

Constituent parts of a complete innervation mechanism--The special
duty of the peripheral terminations of afferent nerves--The specific
qualities of nerve cells--Analogy between the innervation mechanism
of the salivary glands and that of the deeper-lying glands of
digestion--The exciting agencies of the nervous mechanism of the
salivary glands; their particular properties--Differences between
the exciting agencies of the different salivary glands--Discussion
of the sham feeding experiment--Mechanical and chemical stimulation
of the cavity of the mouth has no effect on the gastric glands--The
experiment of Bidder and Schmidt relative to psychic excitation of
the gastric secretion--Conditions for success in this experiment--The
passionate longing for food--the appetite--alone brings on the
secretory effect in the sham feeding experiment.

GENTLEMEN,--As you have learned in the last lecture, and also in part
have seen by direct experiment, the nervous system can influence the
work of our glands in the most diverse ways. The vagus nerve, already
burdened with many duties, has, in addition, proved itself to be an
undoubted exciter of the gastric glands and of the pancreas. But we
must also assign to the sympathetic nerve a similar _rôle_. This is a
matter which cannot be doubted, so far as the pancreas is concerned,
and is highly probable as regards the stomach. We also saw good reason
for believing that these two nerves contained two different classes
of fibres, secretory and trophic, a condition which had already been
proved to exist by Heidenhain for the nerves of the salivary glands.
As a hypothesis we might even have proceeded a step farther and have
divided Heidenhain’s trophic nerves into separate classes of secretory
fibres. Lastly, we advanced important experimental evidence to show
the existence of special inhibitory fibres to the glands, and these
fibres also run in the vagus, the list of whose functions seems almost
interminable.

We obtained these results by division and artificial excitation of
the nerves which run to the glands. But when, how, and by what means
these nerves are thrown into activity during the normal course of
physiological events remains a question.

In order to avoid repetition, and at the same time impart the utmost
clearness to our representation, it may be useful to bring before your
minds at once the plan of innervation of a given organ, all the more
since this scheme is seldom completely followed out or adequately
described in physiological text-books. Consequently, it is not borne in
mind with sufficient precision by the majority of medical men.

A complete innervation mechanism consists of the peripheral endings of
the centripetal (afferent) nerves, the centripetal nerves themselves,
the nerve cells (a group of nerve cells connected with each other is
termed a “nerve centre”), the centrifugal (efferent) nerves, and,
lastly, their peripheral terminations. Physiology now accepts it as a
settled fact, that nerve fibres serve only as _conductors_ of nervous
impulses, which come in from contiguous links of the nervous chain.
Only the peripheral endings of nerves and the nerve cells themselves
have the power of transforming the external stimulus[29] into a
nervous impulse. In other words, in the intact organism these alone
constitute the normal receiving apparatus of the nervous system.
Whether the peripheral ends of centrifugal (efferent) nerves are
likewise able to function as normal sites for the application of
external stimuli has still to be answered. Consequently, when any
external agency excites the peripheral terminations--the receiving
stations--of centripetal nerves in this or that organ, the effect
of the stimulus will be conveyed through the centripetal nerves, as
through a receiving wire, to the central station--the nerve cells. Here
it becomes changed into a definite impulse and now comes back along the
centrifugal nerves--the outgoing wires.

The utmost importance is to be attached to the fact that only the
peripheral endings of centripetal (afferent) nerves, in contrast to
nerve fibres themselves, respond to _specific_ stimuli; that is to
say, are able to transform definite kinds of external stimuli into
nervous impulses. The function of the end organs with which they are
connected is therefore of a purposive nature; in other words, these
organs are only called into play by certain definite conditions, and
impart the idea of being aware of their purpose, of being conscious
of their duty. We have long known that the peripheral endings of
sensory nerves are possessed of a high degree of speciality, and cannot
therefore have any doubt regarding the specific nature of the end
organs of other centripetal nerves. This is a sore point in present-day
physiology. But, notwithstanding our knowledge of the separate parts
of the animal body, we shall only be able to form a true conception
of the motive agencies of the whole complicated machine, when we have
established the specific excitability of the end apparatus of every
centripetal nerve, and have discovered all the mechanical, chemical,
and other factors which throw this or that end apparatus into an active
condition. I always look upon it as a period of scientific inadequacy
so long as the effects of the most diverse external agencies upon any
normal physiological process are admitted to be indistinguishable. As
the work of the digestive canal is now represented in the majority of
text-books, and consequently presented to the mind of the physician,
it bears the impress of this period. To impart to the physician a more
correct conception of this matter was my chief object in giving these
lectures. I hope, indeed, to furnish you with evidence sufficiently
convincing, that the alimentary canal is endowed not with mere general
excitability; that is to say, does not respond to every conceivable
form of agency, but only to special conditions which are different
for the different portions of its length. Just as men and animals in
the world are only able to maintain their existence and constantly
adapt themselves to changing circumstances by aid of the peripheral
endings of their sensory nerves, so every organ, indeed every cell
of every organ, can only maintain its place in the animal microcosm,
and adapt itself to the activity of innumerable associates, as well
as to the general life of the whole, by virtue of the fact that the
peripheral end apparatus of its centripetal nerves possesses a specific
excitability.

The same applies to the nerve cells: obviously they are endowed
with specific sensibility. Irrespective of the excitations which
are communicated to them from centripetal nerves, they respond, as
originators of nervous impulses, only or at least mainly to definite
forms of mechanical, chemical, or other stimuli arising in the
organism. This follows not alone from a number of physiological facts
but also from various pharmacological data. Thus we learn that various
drugs excite or annul the activity of definite portions of the nervous
system, at least in the earlier phases of their effects. This specific
excitability of nerve cells, just as much as the same property of
peripheral end organs, lies at the bottom of the purposive action of
these organs.

Hence, our next duty is to endeavour to discover the normal exciting
conditions of the centripetal nerves belonging to the glands which
we had under consideration in our last lecture, or, more correctly,
to find out the conditions which excite the centres, as well as the
peripheral endings of the different nerves, which form parts of the
nervous apparatus of these glands. We have, therefore, for each phase
of the work of secretion, to find out that portion of the nervous
mechanism which is for the time being under excitation, and to
discover the primary agency by which this condition is elicited. This
would include an exact analysis of the stimulating influence which
mastication and food exert upon the nervous mechanism of these glands.
We shall also be able more fully to comprehend the inner mechanism
underlying the facts which formed the subject of the second lecture.
This, of course, is an ideal programme which we can only follow out
as far as the present state of physiology permits. It may now be
instructive, and, for our further conclusions, advantageous, to glance
shortly at the nervous control of the salivary glands.

The salivary glands, whose innervation has long ago been investigated,
have generally been accepted as types of the deeper-lying digestive
glands, and when it became necessary to form a conception of the mode
of activity of the latter, medical science resorted to a bold analogy
and thought of the nervous apparatus of the salivary glands. But
the attempts of investigators to apply rigidly to others the scheme
of innervation which holds good for the salivary glands, have done
considerable harm to the usefulness of the analogy and have prevented
our arriving at a correct idea of the plan of innervation of the
abdominal glands. We have already had an example of this nature before
us. In the salivary glands we have no clearly marked indications of
nervous inhibition, and this circumstance has decidedly retarded
the due development of our knowledge of the nervous control of the
abdominal glands. Authors naturally expected to see a simple and
prompt stimulation-effect from the same conditions of experiment which
sufficed for the salivary glands, and the failure of this gave them,
as they thought, the right to deny the existence of any extrinsic
nervous influence upon the abdominal glands. The error is now obvious;
the abdominal glands behave in some ways different from the salivary
glands, and for their successful investigation, other conditions of
experiment are necessary than those which held good for the former. In
the working of the abdominal glands nervous inhibitory processes play
a large part, but they are almost wholly absent in the case of the
salivary glands. This is an additional warning that one must never push
the conclusions drawn from analogy too far, but must constantly bear in
mind that the life-functions of all organs are extremely complicated,
and that the work of even the most apparently similar organs should
be submitted to separate and careful observation. To me it appears
that the unjustified analogy drawn between the abdominal and salivary
glands has to be credited with another important misapprehension.
And precisely for this reason I think it desirable to bring under
consideration, if only in brief fashion, the conditions of work of the
salivary glands, especially since Dr. Glinski has instituted in the
laboratory some easily performed experiments which bear upon the matter.

The experiences of daily life teach us from the outset, that the
activity of the salivary glands begins even before the introduction
of food into the mouth. With an empty stomach, the sight of food or
even the thought of it is sufficient to set the salivary glands at
once into activity; indeed, the well-known expression, “to make one’s
mouth water,” is based upon this fact. Hence a psychic event, the eager
longing for food, must be accepted as an undoubted excitant of the
nervous centre for the salivary glands. On the other hand, the same
every-day experience, as well as numerous experiments upon animals,
teach us that a number of substances, when brought into contact with
the mucous membrane of the mouth, are likewise able to call forth a
secretion of saliva. One even acquires the impression that everything
brought into the mouth may reflexly influence these glands, the only
difference being a gradual shading off in the effect, dependent upon
the strength of the stimulation which the substance introduced is able
to exert, and it appears to me that it is precisely this impression
which has driven the idea into the background, that the peripheral
end apparatus of the centripetal nerves of the digestive canal are
specifically excitable. The facts were here correctly observed, but
their indications erroneously interpreted.

The great multiplicity of excitants of salivary secretion, has without
doubt, some connection with the complicated physiological functions
of the saliva. This is the first fluid encountered by everything
which enters the alimentary canal. It must, therefore, in a sense
play the part of host to every substance taken in--moisten the dry,
dissolve the soluble, envelop the hard and bulky with mucus in order to
facilitate its passage down the narrow œsophagus; and submit certain
forms of food material, such as starch, to a process of chemical
elaboration. Nor is its duty by any means ended here. The saliva is
secreted in the first compartment of the alimentary canal, which is at
the same time the sorting-room of the organism. Much of what enters the
mouth may prove in the testing process to be useless, or even noxious,
and must either have its deleterious properties neutralised or be
completely rejected. The saliva is secreted in the first instance to
obviate injurious effects in some way; thus, for example, a strong acid
is to a certain degree neutralised, while other corroding substances
may be simply diluted, and by mere reduction of concentration have
their harmfulness diminished.

In the second place, when the injurious substances have to be wholly
removed, the saliva plays the _rôle_ of a washing-out fluid; otherwise
the material, by clinging to the mucous membrane of the mouth, might in
longer or shorter time gain entry into the blood and there develop its
noxious influence. This last function of the fluid is hardly taken into
account at all in physiology, and yet it is evident that the saliva,
as a cleansing fluid, must have a wide importance. If you only think
of how often we are impelled to expectorate, that is, to wash out the
mouth with saliva after something unpleasant, this will be clear.
Such a view finds additional support when we reflect that a feeling
of disgust produces almost as strong a flow of saliva as the sight
of a tasty meal. In both cases the secretion performs the office of
forerunner: in the first it prepares for the washing out of the mouth,
in the second for the requisite elaboration of the food. Think how
often, when something disagreeable enters the mouth, with what rapidity
the saliva is poured out, even after the unpleasant substance has been
for a considerable time removed, and not a trace more is apparent to
the sense of taste. Indeed, long afterwards one has only to recall
the circumstances to mind in order to bring on anew the secretion of
saliva. Apparently the psychic excitation of the nerves of salivary
secretion also ushers in the act of vomiting, which, as is well known,
can be called forth by mental influence. Further, the function of the
saliva just mentioned is probably the true physiological explanation of
the feeling of disgust which many persons experience at the sight of
the secretion itself.

Hence I hold that substances which obtain entry to the mouth set up a
secretion of saliva only because we have here the seat of a definite
physiological sense, and not because the peripheral terminations of the
buccal nerves are devoid of specific excitability, and capable of being
thrown into action by every desired form of stimulus. In other words,
the specific excitability of the peripheral endings of the salivary
nerves is very comprehensive and widely extended. This is no picture
of the imagination, for it can be supported by facts. To say nothing
of the testimony of earlier authors, that the salivary glands have
each particular exciting agencies to which they specially respond, we
can demonstrate the following facts from the material collected in our
laboratory.

Dr. Glinski isolated the orifices of the salivary glands in dogs with
portions of the adjoining mucous membrane, brought them out of the oral
cavity, and caused them to heal into the edges of the skin wounds. In
his first animal the ducts of the submaxillary gland were thus led
outwards. By means of a Mendeljeff’s clip, the wide end of a conical
funnel of waterproof material was attached to the skin surrounding
the orifice. To the narrow end a small test-tube, which served to
collect the saliva, was attached by a wire. I now offer such an animal
a piece of flesh, and, as you see, the tube fills up at once with
saliva. I stop tempting the dog, hang on a new test-tube, and give it
a few pieces of flesh to eat; once more a strong secretion of saliva
results. A new tube is now attached to the funnel, the dog’s mouth is
opened, and a pinch of fine sand thrown in; again there is a flow of
saliva. Once more a new test-tube; and now I apply to the buccal mucous
membrane, the plume of a feather dipped in acid solution, with the
result that I obtain a strong flow of saliva. One may employ a number
of substances in this way, when a similar effect is always produced.
You see, in this, such a comprehensive excitability of the innervation
apparatus of the salivary glands that you might readily interpret it as
meaning the power of response to all and sundry forms of stimulation.
We now proceed, however, to another dog, whose parotid duct has in
a similar manner been diverted outwards. The saliva is collected in
the same way. We tempt the dog with a piece of flesh, but to our
astonishment no saliva flows, and yet the animal is most eager for the
savoury meal offered. Now we give it some raw flesh to eat; again the
secretion of saliva is as good as absent; only when I come near can I
detect one or two drops of saliva running down the sides of the tube.
Probably you will say there is something wrong, either with the method
or with the glands of the animal. But wait a little. I now give the dog
finely powdered dry flesh, and obtain at once an abundant secretion.
Should any one happen to think that the variation in the result is
dependent, not on a different specific activity of the glands, but on
individual differences in the dogs, I respond that Dr. Glinski has had
an animal with double parotid and submaxillary fistulæ, and was able to
observe on one and the same dog, a like behaviour on the part of the
glands to that which we have just seen in two different individuals. An
analogous experiment with bread was also carried out by Dr. Glinski.
The eating of fresh moist bread produced no secretion worth mentioning,
while dry bread, on the other hand, caused the saliva to flow in large
quantities. The results of this experiment permit us to draw extremely
instructive conclusions. In the first place, the several salivary
glands are, as a matter of fact, very sharply differentiated in the
conditions necessary for their activity--that is to say, in respect
to the agencies which excite their nervous mechanisms. Secondly, the
innervation apparatus of the parotid manifests a very sharp selective
power in the choice, so to speak, of an adequate stimulus. The
mechanical effect of large pieces of flesh is naturally much greater
than that of the finely powdered material, and yet it was precisely
to the latter that the glands responded. The stimulus is, therefore,
not due to the mechanical, but to some other property of the food.
This other property is obviously the dryness of the material. Our
example illustrates how that which we may term “purposiveness” comes
into play in the working of our glands and also how erroneous is the
opinion that the mechanical stimulus is all potent. Indeed, previous
authors have already pointed out that dry substances cause a specially
free secretion of saliva, and yet physiological opinion throughout the
length and breadth of the land, as expressed in text-books, has chosen
to recognise a _universal_ instead of a _specific_ excitability. Dr.
Wulfson, who is at present carrying on the investigation of salivary
secretion in our laboratory, has added a very interesting observation
to the results of Dr. Glinski already related. The parotid gland, which
is hardly, if at all, excited when one offers fresh meat to the animal,
responds with a very active secretion, when dry food (bread or powdered
meat) is offered. This phenomenon is all the more surprising since the
desire of the animal for eating is much more strongly excited by flesh
than by dry bread. I am quite convinced that an exact study of the
exciting agencies of the three salivary glands will furnish a number of
new data bearing upon the question in hand.

The second reagent which is poured out on the raw material in the
digestive canal is the gastric juice. How, in the normal course of
events, is the work of the gastric glands, which prepare this juice,
called into play? With the first, and manifestly important factor,
which has a relation thereto, you are already acquainted, and, indeed,
have already seen. I refer to the production of gastric juice in the
empty stomach, as a result merely of the swallowing of food in the
so-called sham feeding of an œsophagotomised dog. When one takes
into consideration the absolute independence of this factor, and the
intensity of the effect, which makes itself evident in the secretion of
a large quantity of juice of high digestive power, the exciting agency
which brings about such secretion must be recognised as one of the most
important and effective processes in gastric digestion. But in what
does it consist? At first sight it appears--and when I previously drew
your attention to the fact I expressed the opinion--that there is here
a simple reflex effect from the cavity of the mouth upon the secretory
nerves of the stomach, similar to the reflex excitation, _e.g._, of the
parotid gland, by finely powdered flesh thrown into the mouth. Now,
however, I assert quite emphatically that this is not the case. We
have, it is true, in the activity of the salivary glands an analogous
phenomenon to indicate--not, however, that of which we have just
spoken. We might apply every conceivable form of stimulus which could
possibly come into play in the act of eating, and yet would not obtain
the slightest indication of secretory activity in the stomach. In this
dog with a gastric fistula, and with also a divided œsophagus, I will
try such an experiment, using the most effective chemical stimulus to
the buccal mucous membrane, viz., acid solution.

The secretion of saliva begins at once, as you see; the acid is,
therefore, effective. From the stomach, however, in spite of continued
excitation, no secretion results, although the acid, mixed with the
saliva, is swallowed and flows out again from the upper segment of the
œsophagus--that is to say, passes along precisely the same path that
the food takes in sham feeding.

We could experiment in the same way with a number of other substances:
saline, bitters, pepper (strong local excitation), mustard, and so
on, and always with the same results; a free secretion of saliva, but
perfect quiescence of the gastric glands. We may even, with the same
object, employ the soluble constituents of flesh in the form of a
decoction, and likewise observe, in most cases at least, no sign of
activity on the part of the gastric glands.

With the chemical we may also combine a mechanical stimulus. We can,
for example, wipe out the mouth with a sponge soaked in the solution
to be experimented with, but always with the same negative result.
We may finally give such pieces of sponge, or even smooth stones of
considerable size, to the dog to swallow, passing them back behind the
anterior pillars of the fauces and allowing them to fall out again,
from the upper portion of œsophagus. It may be added that a well-taught
dog puts up with all these procedures without the slightest protest.
You see that all the manipulations in this case are carried out with
bare hands and without instrumental aid. One can easily train a dog
to swallow stones which are placed in the anterior part of the buccal
cavity. It simply makes a few chewing movements and swallows them down.
The dog on which the acid experiment has just been made serves also for
the swallowing of the stones. The attendant now places some pebbles in
the front part of the mouth, when the animal rolls them round, as if
chewing and gnawing them, and then swallows them. The stones fall out,
as you see, from the œsophagus, and drop with an audible sound upon
the table. This play with the stones has now lasted fifteen or twenty
minutes (in the laboratory we have often kept it up for hours), and yet
not a drop of gastric juice is to be seen.

In order to prove that the dog is perfectly healthy and normal, we lay
aside the stones and proceed to our old experiment of sham feeding. As
you see, the first drop of gastric juice makes its appearance precisely
at the end of five minutes, and after a further five minutes we have
collected more than 15 c.c. of the fluid; consequently there can be no
doubt that in this dog both gastric glands and nerves are uninjured
and function in normal manner. At one time we even had a dog which
voluntarily took the stones out of one’s hand and swallowed them; the
sagacious creature had seen our object in previous experiments and
learned to perform it of its own accord! But in this case also the
result was negative.

Clearly, therefore, neither chemical nor mechanical stimulation of
the buccal mucous membrane is capable of reflexly exciting the nerves
of the stomach. Further, it is obvious that the excitation of these
nerves in sham feeding is not the result of a stimulation coincidently
produced; that is to say, the excitement of the chewing and swallowing
centres does not imply simultaneous action of the secretory centre of
the gastric glands. In what, then, does this influence consist which
is intrinsic to the sham feeding, but which we have not been able to
reproduce in our analytical investigation? There is only one thing
to think of, namely, the eager desire for food, and the feeling of
satisfaction and contentment derived from its enjoyment.

It has, indeed, been known for forty years, thanks to the experiments
of Bidder and Schmidt, that at times, the offering of food to a
hungry dog, in other words, the excitement of a keen desire for
it, is sufficient to cause a flow of gastric juice from the empty
stomach. We shall presently have occasion to observe the force of this
physiological factor. Here I bring before you another dog, likewise
having a gastric fistula with divided œsophagus. The stomach has been
washed out half an hour ago, and since then not a drop of gastric juice
has escaped. We begin to get ready a meal of flesh and sausage before
the animal as if we meant to feed it. We take the pieces of flesh from
one place, chop them up, and lay them in another, passing them in front
of the dog’s nose, and so on. The animal, as you see, manifests the
liveliest interest in our proceedings, stretches and distends itself,
endeavours to get out of its cage and come to the food, chatters its
teeth together, swallows saliva, and so on. Precisely five minutes
after we began to tease the animal in this way the first drops of
gastric juice appear in the fistula The secretion grows ever stronger
and stronger, till it flows in a considerable stream. After the
lapse of a few minutes we can count the number of cubic centimetres
by tens. The meaning of this experiment is so clear as to require no
explanation; the passionate longing for food, and this alone, has
called forth under our eyes a most intense activity of the gastric
glands. If the experiment be frequently repeated, one can easily
observe that the keener and more eager the desire on the part of the
dog for the food, the more certain and intense is the secretory effect.
In extreme cases there is even a quantitative relationship between this
effect and that of the sham feeding.

Here is an experiment of Professor Ssanozki, in which the secretory
effect of the mere tempting of the animal with the sight of food is
compared with that of sham feeding. A few threads of alkaline mucus
had just escaped from the stomach, and then the excitation of the dog
with flesh was begun. After six minutes the secretion commenced and
continued as follows:

Duration of the flow. Quantity of the juice.
8 minutes 10 c.c.
4 ” 10 ”
4 ” 10 ”
10 ” 10 ”
10 ” 10 ”
8 ” 10 ”
8 ” 10 ”
19 ” 10 ”
19 ” 3 ”

Then followed a sham feeding for six minutes.

Duration of the flow. Quantity of the juice.
17 minutes 10 c.c.
9 ” 10 ”
8 ” 10 ”

It is clear that in this case the tempting, instead of being less
effective than the sham feeding, on the contrary excelled it.

Consequently, the observation of Bidder and Schmidt was perfectly
correct. It cannot, however, be said that it received general
recognition in physiology, or that it was sufficiently appreciated.
There are authors who could never convince themselves of its reality,
and in many physiological text-books it is not once mentioned. By
way of explanation, we shall now consider how this matter must be
dealt with by those who wish to observe the effect. It is only under
certain conditions that it can be seen. Firstly, the animal must be
healthy and vigorous; it must have a perfectly uninjured gastric
mucous membrane; and this, from the description in the case of many
authors who obtained a negative result, was not the case. Secondly,
the success of the experiment, as stated above, is dependent upon the
intensity of the desire for eating, and this, again, is dependent
upon how freely and how long beforehand the dog had eaten, and also
upon what it is tempted with, whether with a dish that excites its
desire or leaves its interest unawakened. It is known that dogs have
very different tastes, just as men have. Thirdly, one may find among
the dogs positively careless, indifferent creatures, incapable of
being perturbed in this way by anything which has not actually reached
their mouths, and patiently waiting till the food is given them. Hence
for success in the experiment, eager, impressionable, and excitable
animals are necessary. Fourthly, one has to reckon with the sense and
cunning of the dog, a factor which is not lightly to be disregarded.
Often the animals perceive at once that they are only being teased
with the food, become annoyed thereat, and turn away offended at what
is being done before them. We must, therefore, so arrange matters as
if the animals were not going to be disappointed but fed in reality.
If attention be paid to these conditions the experiment of “psychic
excitation of the gastric secretion,” as we usually term it, will be
found to be as reliable as the experiment of sham feeding. When one is
occupied for a length of time with the study of the gastric secretion
under different conditions, one becomes convinced of what a dangerous
source of error this psychic excitability may become in the different
experiments. We must constantly fight, so to speak, against this
factor, keep it ever in view, and guard against it. If the dog has not
eaten for a long time, every movement,--the going out of the room, the
appearance of the attendant who ordinarily feeds the animal--in word,
every little triviality may give rise to excitation of the gastric
glands. The minutest attention is necessary in order to avoid such
sources of error, and we should not be far wrong if we said that much
which has been ascribed in former investigations to the effect of this
or that agency was in reality a result of unobserved psychic influence.
Consequently, in order to verify our own conclusions concerning the
effects of this or that condition, we have performed many of our
experiments on sleeping animals, having beforehand convinced ourselves
by frequent repetition that sleep exercises no restraining influence on
the working of the gastric glands.

When we recall to mind the failure of our attempts to obtain a
secretion of gastric juice by any stimulation whatever of the buccal
mucous membrane, and at the same time see how constant and intense the
action of this psychic impression is, we are forced to the inevitable
conclusion that in our sham feeding experiment the whole secretory
effect is due to the psychic stimulus, that is to say, to the keen
desire on the part of the animal for food and the satisfaction of
enjoying it.

In view of the importance of the act of eating, which even now is
apparent, but which will become still more obvious when the succeeding
periods of secretion are investigated, we have spared neither time nor
trouble to arrive at a correct explanation of the mechanism of this
factor. We have, therefore, taken in hand a number of modifications of
the sham feeding experiment, and these investigations have confirmed
the opinion at which we had arrived. If, for instance, the dog has
been prepared by a long fast of two to three days, a very intense
secretion of gastric juice will always be obtained by the sham feeding
experiment, no matter what may be given it to eat, whether boiled or
raw flesh, bread or coagulated egg-white, etc. The dog, however, which
has not fasted, that is to say has been fed fifteen to twenty hours
before, will pick and choose amongst the different foods, eating one
with great greed, tolerating another, and refusing altogether a third,
and, corresponding therewith, the amount and quality of the gastric
juice will manifest wide variations. The more eagerly the dog eats
the more juice will be secreted and the greater the digestive power
which it possesses. The majority of dogs prefer flesh to bread, and
correspondingly less juice will be produced by sham feeding with bread
than with flesh. Sometimes, however, we find dogs which will devour
bread with greater appetite than flesh. In these cases one obtains
more and stronger juice in sham feeding with bread than with flesh.
Here is a case in point: a dog is given boiled meat which has been
cut into pieces of definite size, and the pieces follow each other
at regular intervals of time. The animal eats, but soon, from its
behaviour, you see that it develops no particular greed for the meal,
and this observation is confirmed by the fact that after fifteen to
twenty minutes it ceases taking the flesh. The secretion of juice has
meanwhile either not begun at all, or only after a longer interval
than five minutes, and remains scanty to the end. Now wait till the
secretion has stopped and give the same dog raw flesh, either forthwith
or next day, in pieces of the same size and at the same rate as
before. The raw meat tastes excellently to the dog; it eats for hours
at a time; the secretion of gastric juice begins precisely after five
minutes and is very active. With another dog which prefers boiled to
raw meat exactly the reverse occurs. Broth, soup, milk--towards which
dogs are usually more indifferent than towards solid food--often
produce in sham feeding either no secretion at all or only very little,
although broth, for instance has essentially the same taste as flesh.

It is therefore clear that in sham feeding the psychic effect may
readily become an absolute and independent factor. All the conditions
which we enumerated above, and which are necessary for the successful
production of the psychic effect, hold good in combined form for the
sham feeding experiment. The dog eats with greed before one’s eyes;
the food which it receives is pleasant; it not only imagines food but
actually eats it, and has therefore no reason to feel offended, for
naturally the idea does not occur to any of the dogs that all their
trouble is in vain.

Consequently, in the sham feeding experiment, by the act of eating,
the excitation of the nerves of the gastric glands depends upon a
psychical factor which has here grown into a physiological one, that
is to say, is just as much a matter of course, and appears quite as
regularly under given conditions as any other physiological result.
Regarded from the purely physiological side, the process may be said
to be a complicated reflex act. Its complexity arises from this, that
the ultimate object is attained by the joint working of many separate
organic functions. The material to be digested--the food--is only found
outside the organism in the surrounding world. It is acquired not
alone by the exercise of muscular force, but also by the intervention
of higher functions, such as judgment, will, desire. Hence the
simultaneous excitation of the different sense organs, of sight, of
hearing, of smell and taste, is the first and strongest impulse towards
the activity of the gastric glands. This especially applies to the two
latter senses, since they are only excited when the food has already
entered the organism, or at least has arrived very near it. It is by
the establishment of this passionate desire for eating that unerring
and untiring nature has linked the seeking and finding of food with the
commencement of the work of digestion. That this factor, which we have
now carefully analysed, stands in closest connection with an every-day
phenomenon of human life, namely, appetite, may easily be predicated.
This agency, which is so important to life and so full of mystery to
science, becomes here at length incorporated into flesh and blood,
transformed from a subjective sensation into a concrete factor of the
physiological laboratory.

We are therefore justified in saying that the appetite is the first
and mightiest exciter of the secretory nerves of the stomach, a factor
which embodies in itself a something capable of impelling the empty
stomach of the dog in the sham feeding experiment to secrete large
quantities of the strongest juice. A good appetite in eating is
equivalent from the outset to a vigorous secretion of the strongest
juice; where there is no appetite this juice is also absent. To restore
appetite to a man means to secure him a large stock of gastric juice
wherewith to begin the digestion of the meal.

LECTURE V

PERIOD OF OCCURRENCE AND IMPORTANCE OF THE PSYCHIC OR APPETITE JUICE
IN THE SECRETORY WORK OF THE STOMACH--THE INEFFICIENCY OF MECHANICAL
STIMULATION OF THE NERVOUS APPARATUS OF THE GASTRIC GLANDS

The psychic secretion is the normal commencement, in the majority of
cases, of secretory activity on the part of the gastric glands. If
the meal be subdivided and administered at intervals, the psychic
juice appears each time--Demonstration of “appetite juice” in a dog
with an isolated gastric _cul-de-sac_. The work of the gastric glands
if appetite juice be avoided by introducing food through a gastric
fistula unperceived by the animal--Digestion of flesh by the stomach
with and without sham feeding--Duration of the secretory influence of
sham feeding--After the cessation of the psychic effect, how is the
secretory work of the stomach maintained?--Experiments to prove the
ineffectiveness of mechanical stimulation: excitation of the mucous
membrane by means of a glass rod, a feather, a puff of sand, and by
rhythmic dilatation of an india-rubber ball--Contact between the food
and the stomach-wall may indirectly call the activity of the glands
into play by awakening or increasing the desire for food.

GENTLEMEN,--On the last occasion we made ourselves acquainted with
the first normal impulse which, in the natural course of events,
calls into activity the innervation apparatus of the gastric glands.
This impulse is a mental one, and consists in a passionate longing
for food, that which in every-day life, and in the practice of the
physician, is called “appetite,” and which everybody, both medical
and lay, endeavours carefully to promote. We may now venture to say
explicitly, APPETITE IS JUICE, a fact which at once displays the
pre-eminent importance of the sensation. Medical science endeavours to
assist the debilitated stomach by introducing the active constituent of
gastric juice--pepsin--from without, or by prescribing other remedies
believed to promote its secretion. It is, however, of interest to
follow our experimental investigation still farther. What position is
to be assigned to the “psychic” or “appetite-juice”[30] in the course
of normal gastric digestion? Is any definite _rôle_ to be attributed
to it? What course does gastric digestion take when it is absent?
Fortunately to all these important questions satisfactory answers are
forthcoming by experiment. We have only to regret that these answers
come so late.

Let us recall to memory how the secretion of gastric juice proceeded
after feeding with flesh or bread in the case of our dog with the
isolated miniature stomach. The following are the quantities and
digestive capabilities of the first two hourly portions of juice after
the administration of 200 grams of flesh or bread (experiments by Dr.
Chigin):

═════╤═══════════════════╦═══════════════════
│ Flesh. ║ Bread.
Hour.├————————-┬————————-╫—————————┬—————————
│Quantity │Digestive║Quantity │Digestive
│of juice.│ power. ║of juice.│ power.
—————┼————————-┼————————-╫————————-┼—————————
1st │12.4 c.c.│ 5.43 mm.║13.4 c.c.│ 5.37 mm.
2nd │13.5 ” │ 3.63 ” ║ 7.4 ” │ 6.50 ”
————-┴—————————┴————————-╨—————————┴—————————

You see at once that the secretion of the first hour is identical in
the two cases both as regards quantity and digestive power, and only in
the second is the secretory work differentiated according to the nature
of the food. How are we to explain the secretion which takes place at
the commencement? Is it not the same which we have already seen in the
sham feeding experiments? Is not this first onrush of the stream of
secretion the preliminary psychic juice? Unquestionably, gentlemen,
this is the case, and we may convince ourselves of the fact in the
most diverse ways. Above all, the following is clear: whatever occurs
in the so-called sham feeding cannot wholly be absent in the case of
normal feeding, since the former is nothing else than the isolated
commencement of normal digestion. This justifiable inference is fully
confirmed, if the secretion of the first hours after the administration
of flesh and bread be compared with that after simple sham feeding. In
the case of feeding with flesh and bread, the identically similar and
high digestive power of the first hourly portions is striking, and this
power coincides with what we have met in sham feeding. Further, if the
quantity of juice from the miniature stomach during the first hour be
compared with that produced by the non-resected part of the organ,--to
do which we must multiply it by ten, since the resected _cul-de-sac_
is approximately one-tenth of the whole organ,--it is here again found
that the quantity approximately corresponds to the mean values obtained
by sham feeding. Finally, the depression in digestive power or quantity
of juice (with flesh, decrease of digestive power; with bread, decline
in the quantity of juice), which sets in soon after the taking of food,
indicates that the two conditions are connected with the ingestion
of food--_i. e._, with a transitory factor which soon passes away
and gives place to other conditions. Our explanation becomes still
more convincing when we take into consideration the effects of other
foods. If you give the dog, for example, something else to eat which
does not interest it to the same degree as flesh or bread, you will
find the initial increase in quantity and strength of juice does not
appear. Offer the animal milk, for example, which in sham feeding,
especially if it does not last long, calls forth, as a rule, no
secretion, or at all events only very little, and the rapid flow of the
commencement--the already-mentioned initial rise--absolutely fails to
appear. You have already seen the figures which deal with this matter;
I think it necessary, however, to bring them forward again in order
that you may be better able to compare them with the secretion after
flesh and bread.

The dog was given 600 c.c. of milk (experiment by Dr. Chigin).

Hour. Quantity of juice. Digestive power.
1st 4.2 c.c. 3.57 mm.
2nd 12.4 ” 2.63 ”

We have now begun the analytical examination of the variations of our
secretory curve. But owing to the importance of the matter we did not
confine ourselves to conclusions which might be drawn from earlier
investigations. We turned to new forms of experiment for further proof.

Thus we divided the ordinary ration of flesh given to our dogs--400
grams--into four equal parts, which were administered at intervals of
an hour and a half. (Experiments by Privat docent Kotljar and Dr.
Lobassoff.) Each time after the dog received its 100 grams of flesh we
were able to detect a rise both in the quantity and in the digestive
power of the juice. The following table shows the figures in question:

══════════╤═══════════╤═══════════╤═══════════════════════
Half-hour │ Quantity │ Digestive │
periods. │ of juice. │ power. │ Remarks.
——————————┼———————————┼——————————-┼———————————————————————
1st │ 3.1 c.c. │ 5.13 mm. │ 100 grms. flesh given.
2nd │ 5.0 ” │ 4.63 ” │
3rd │ 4.7 ” │ 4.50 ” │
4th │ 5.4 ” │ 4.88 ” │ 100 grms. ” ”
5th │ 5.5 ” │ 3.38 ” │
6th │ 4.7 ” │ 2.75 ” │
7th │ 6.0 ” │ 3.75 ” │ 100 grms. ” ”
8th │ 5.4 ” │ 2.50 ” │
9th │ 5.9 ” │ 2.50 ” │
10th │ 5.4 ” │ 3.88 ” │ 100 grms. ” ”
11th │ 5.3 ” │ 3.0 ” │
12th │ 4.2 ” │ 2.5 ” │
——————————┴———————————┴——————————-┴—————————————————————————

In the curve which follows, only the variations of digestive power are
represented.

It is clear that the increase, both of digestive power and of juice
volume, is connected with the act of taking in food.

It appeared of interest definitely to determine the volume and
properties of the secretion called forth by the act of eating in the
dog with the isolated stomach. We endeavoured, therefore, at the
beginning, to imitate the conditions of sham feeding as they occurred
in the case of the dog with divided œsophagus. In addition to the
fistular orifice leading into the isolated miniature stomach, another
was opened into the main portion of the organ. If we now fed the dog
in the ordinary way with small pieces of flesh, these were received
back again at the orifice of the latter fistula, covered with saliva.
Precisely as in sham feeding, after five minutes the juice began to
flow simultaneously, from both the large and small stomachs. The
secretion ran a corresponding course in the two cavities and ceased at
the same length of time in both after the administration of food was
stopped. Here is an instance taken from such an experiment performed by
Dr. Lobassoff.

[Illustration: FIGURE 1.--Curve of digestive power constructed from the
foregoing table.]

In five minutes the dog had eaten eighty pieces of flesh (weighing 172
grams), all of which soon afterwards dropped out at the fistula. The
secretion began in both stomachs after the lapse of seven minutes from
the commencement of the feeding, and proceeded as follows:

══════╤═══════════════════════╦══════════════════════════════════
│ Miniature stomach. ║ Main stomach.
├——————————-┬———————————╫—————————————┬————————————————————
Hour. │ Quantity │ Digestive ║ Quantity of │ Digestive power.
│ of juice. │ power. ║ juice. │
——————┼——————————-┼——————————-╫—————————————┼————————————————————
1 │ 7.7 c.c. │ ║ 83.2 c.c. │ 5.35 mm.
│ │ ║ │} In consequence of
│ │ ║ │} a mixture with
2 │ 4.5 ” │} ║ 58.1 ” │ } bile (10-15 c.c.)
│ │ }6.25 mm ║ │ } the digestive
2½ │ 0.6 ” │} ║ 8.5 ” │} power was greatly
│ │ ║ │} reduced.
——————┴——————————-┴——————————-╨—————————————┴————————————————————

The secretion from both cavities also came to an end at the same time.

This experiment proves to us, first, that the main and miniature
stomachs work in perfectly parallel manner with each other. The
beginning, the end, and the intermediate variations of the secretion
correspond in both cases. Secondly, the digestive power of the
secretion coincides in both, and is the same which was observed in the
so-called sham feeding. It has here remained at the same height till
the cessation of the secretion, without falling to the lower value
which we observed from the beginning of the second hour onwards, after
normal flesh feeding.

This was also confirmed later, when we performed an œsophagotomy on the
dog, and carried out sham feeding in typical form. Here follows one of
these experiments taken from Dr. Lobassoff’s article.

The first drop of juice appeared from both cavities during the sixth
minute after commencing the feeding, which was kept up for half an
hour. The further course of the secretion was as follows:

══════╤══════════════════════════╦══════════════════════════
│ Miniature stomach. ║ Main stomach.
├————————————-┬————————————╫———————————————┬——————————
Hour. │ Quantity │ Digestive ║ Quantity │ Digestive
│ of juice. │ power. ║ of juice. │ power.
——————┼————————————─┼————————————╫——————————————─┼——————————
1st │ 7.6 c.c. │ 5.88 mm. ║ 68.25 c.c. │ 5.5 mm.
2nd │ 4.7 ” │ 5.75 ” ║ 41.5 ” │ 5.5 ”
3rd │ 1.1 ” │ 5.5 ” ║ 14.0 ” │ 5.38 ”
│———— │ ———— ║ ————— │ ————
│13.5 (total) │ 5.75 (mean)║123.75 (total) │ 5.5 (mean)
——————┴—————————————┴————————————╨———————————————┴———————————

The secretion came to an end in both stomachs at the same time.

The above is represented in curves in Figs. 2 and 3, the scale on which
that for the main stomach is drawn being ten times less than that for
the small. As you see, the progress of secretion is identical in both.

The existence of a fistula leading into the large stomach affords us
also the possibility of performing an experiment upon our dog which
is exactly the converse of the sham feeding experiment, and which
constitutes a real _experimentum crucis_. While in sham feeding, we
had only, so to speak, the beginning of digestion before us, we are
now able in our cross experiment to start at the continuation of this
beginning. For this purpose it is only necessary to bring the food
into the stomach through the fistula, without attracting the dog’s
attention. Since in this experiment it is above all necessary not to
excite the dog’s appetite, it is best to carry out the procedure on the
sleeping animal. I may add at once, however, that the same result can
be obtained on the waking animal, only the process must be performed
unnoticed, and the animal’s attention must be diverted from thoughts of
food.

[Illustration: FIGURE 2.--Curve of secretion from the miniature
stomach.]

[Illustration:
FIGURE 3.--The same from the main stomach reduced ten times.]

The results of this experiment are striking, and do not in any way
resemble the secretion after normal feeding. Some kinds of food, for
instance bread and coagulated white of the hen’s egg, when directly
introduced into the stomach, do not yield a single drop of juice
during the first hour or more afterwards. This holds good both for
the small and large stomachs. When a glass rod is introduced into the
food contained in the organ it remains dry. Flesh, if introduced at
this stage, is able to excite a secretion, but the appearance of the
juice is considerably retarded. It begins from fifteen to forty-five
minutes after the feeding, instead of from six to ten, is under normal
circumstances extremely scanty during the first hour (3 c.c. to 5 c.c.
instead of 12 c.c. to 15 c.c.), and possesses a very low digestive
power.

Here is an experiment by Dr. Lobassoff:

400 grms. of flesh were brought into the stomach.

Hour. Quantity of juice. Digestive power.
1st 3.7 c.c. 2.0 mm.
2nd 10.6 ” 1.63 ”
3rd 9.2 ” 1.5 ”
4th 7.0 ” 1.88 ”
5th 5.6 ” 2.25 ”
6th 6.6 ” 2.63 ”
7th 7.5 ” 1.88 ”
8th 5.3 ” 2.0 ”
9th 3.0 ” 5.0 ”
10th 0.2 ” — ”

The secretion began twenty-five minutes after introducing the food. I
now ask you to compare the following tables:

┌────—┬——————————————————╥——————————————————╥——————————————————┬———————┐
│ │Fed with 200 grms.║Flesh (150 grms.) ║ Sham feeding │ Total │
│ │of flesh (Chigin).║brought into ║ (Lobassoff). │ quan- │
│ │ ║stomach(Lobassoff)║ │ tity │
│Hour.├————————┬—————————╫————————┬—————————╫————————┬————————-┤ in two│
│ │Quantity│Digestive║Quantity│Digestive║Quantity│Digestive│experi-│
│ │of juice│ power. ║of juice│ power. ║of juice│ power. │ ments.│
│ │ c.c. │ mm. ║ c.c. │ mm. ║ c.c. │ mm. │ │
├—————┼————————┼————————-╫————————┼—————————╫————————┼————————-┼———————┤
│ 1st │ 12.4 │ 5.43 ║ 5.0 │ 2.5 ║ 7.7 │ 6.4 │ 12.7 │
│ 2nd │ 13.5 │ 3.63 ║ 7.8 │ 2.75 ║ 4.5 │ 5.3 │ 12.3 │
│ 3rd │ 7.5 │ 3.5 ║ 6.4 │ 3.75 ║ 0.6 │ 5.75 │ 7.0 │
│ 4th │ 4.2 │ 3.12 ║ 5.0 │ 3.75 ║ — │ — │ 5.0 │
└—————┴————————┴—————————╨————————┴—————————╨———————-┴—————————┴———————┘

The progress of juice secretion in the above is also represented in the
following curves:

[Illustration:
FIGURES 4-7.—A. Ordinary curve of gastric secretion (200 grms.
flesh). B. Curve from direct introduction of food (150 grms. flesh).
C. Sham feeding with same. D. Summation of B and C.]

As you see, the curve which represents the results of the direct
introduction of flesh ascends much more slowly and does not attain
anything like the height of that caused by normal feeding with the same
food. But if the quantities obtained by direct introduction of the
flesh be added to those of sham feeding, the resulting curve is almost
identical with the normal.

In like manner the digestive power of the secretion in the foregoing
experiments can be dealt with, and with the same result. It is a good
instance of how a secretion curve can be synthetically constructed from
its constituent factors.

Finally, I am able to demonstrate to you the following instructive
experiment. In the presence of some of my listeners, whom I had invited
to attend an hour before the lecture, I carried out the following
procedures on two dogs, both of which had ordinary gastric fistulæ and
were, besides, œsophagotomised. Into the stomach of one, while its
attention was distracted by patting and speaking kindly to it in order
to avoid arousing any thoughts of feeding, a definite number of pieces
of flesh were introduced through the fistula. The morsels were threaded
on a string, the free end of which was fastened to the fistular cannula
by inserting a cork. The dog was then brought into a separate room and
left to itself. A like number of pieces was introduced into the stomach
of the other dog in the same way, but during the process a vigorous
sham feeding was kept up, the animal being afterwards left alone. Each
dog received 100 grams of flesh. Since then an hour and a half have
elapsed, and now we may draw the pieces of flesh out by means of the
thread and weigh them. The loss of weight, and consequently the amount
of flesh digested, is very different in the two cases. In that of the
dog without sham feeding the loss of weight amounts to merely 6 grams,
while the flesh withdrawn from the stomach of the other dog weighs only
70 grams, that is to say, was reduced by 30 grams. This, therefore,
represents the digestive value of the passage of food through the
mouth, the value of an eager desire for food, the value of an appetite.

I give also a series of figures obtained by Dr. Lobassoff in analogous
experiments. Into the dog’s stomach 25 pieces of flesh (100 grams)
were brought. The flesh remained two hours in the cavity. Without sham
feeding 6.5 per cent, with eight minutes' sham feeding 31.6 per cent,
of the quantity was digested.

Again: the flesh remained an hour and a half in the stomach; without
sham feeding 5.6 per cent, with five minutes' sham feeding 15 per cent,
was digested.

Once more: the flesh remained five hours in the stomach; without sham
feeding 58 per cent, with sham feeding 85 per cent, was digested, the
balance of undigested food being 42 per cent in the one case and 15 per
cent in the other.

I must, however, add that from the nature of this experiment it is not
well adapted for class demonstration, and may often fail. On the one
hand, it is not at all easy to conceal the introduction of the flesh
from the dog; on the other, the unusual and distracting surroundings
of the animal often causes a short period of sham feeding to have less
effect than would otherwise pertain. In order to avoid such failures
it is better before an audience to carry out this experiment only
on dogs accustomed to appear in the lecture theatre, and of whose
temperament the experimenter is well assured.

I hope you have now been convinced of the great importance which is to
be attached to the passage of food through the mouth and œsophagus, or,
in other words--and this, according to our former experiences, means
the same thing--to the eager desire for food. Without this longing,
without the assistance of appetite, many forms of food-stuffs which
gain entry to the stomach remain wholly devoid of gastric juice.
Others, it is true, excite a secretion, but the juice poured out is
scanty and weak.

It is only later, when we have still more fully recognised the
conditions upon which the secretory work of the gastric glands depends,
that we shall be able to grasp the meaning of these facts in a more
comprehensive manner. For instance, why does bread brought unnoticed
into the stomach of the dog cause no secretion for hours, while flesh
tolerably soon (after twenty to forty minutes) provokes this act? This
will be explained in the next lecture; now, however, we must consider
other questions.

How long does the after-effect, the echo of the first impulse to the
secretory nerves of the stomach, continue to last? How long does
appetite juice continue to flow after the normal act of eating, which,
especially in the case of animals, is not of long duration? We have
already determined many times, not only on our dog with the isolated
stomach, but also on other animals, how long the after-effect of sham
feeding is continued.

Here, for example, is an experiment from the article of Professor
Ssanozki which deals with the point. The dog had a gastric fistula and
also an opening leading into the œsophagus. After a sham feeding of
five minutes the secretion began, and was continued as follows:

Time in minutes. Quantity. Digestive power.
10 25.5 c.c. 8.1 mm.
10 20.0 ” 8.0 ”
10 13.5 ” 6.8 ”
10 11.0 ” 7.5 ”
10 8.5 ” 8.1 ”
10 6.5 ” 9.0 ”
20 13.5 ” 7.4 ”
20 11.0 ” 7.2 ”
20 7.0 ” 7.2 ”
20 11.5 ” 6.8 ”
20 11.0 ” 6.5 ”
30 6.5 ” 7.6 ”
20 5.5 ” 7.2 ”

The effect, therefore, even after a short period of sham feeding,
stretches over a length of time. Naturally the same holds good for the
taking of food in the normal way. One must, however, bear in mind that
in sham feeding, with all the force and reality of a hunger sensation
not satisfied, the eager desire for food, the effective agency, becomes
more and more accentuated, and therefore the secretory influence is
prolonged and more powerful. In normal feeding, however, the quelling
of the longing, the feeling of satisfaction which, as is well known,
sets in long before the termination of the digestive period from the
mere filling and distension of the stomach, must diminish the desire
for food, and, consequently, bring the secretory effect to an end.

It is, therefore, improbable that the whole secretory process in the
stomach, which, in the case of certain kinds and quantities of food,
lasts from ten to twelve hours, is dependent on the factors which we
have up to the present investigated. This is all the more obvious
since a sham feeding of five minutes, even under the most favourable
circumstances, does not call forth a secretion for longer than three to
four hours. We must, therefore, seek for other exciting agencies of the
innervation apparatus of the gastric glands.

Why and wherefore is the secretion instituted by psychic influence
maintained? What would first occur to all your minds is naturally
the immediate influence which the food exerts upon the walls of the
stomach. And this is true, but it does not happen in the simple, direct
fashion current in the minds of many physiologists and physicians. When
I said that bread or boiled white of egg, introduced directly into the
stomach, may not for hours produce a trace of secretion, probably many
of my hearers may have asked themselves with natural astonishment,
“How, then, is the effect of the forced feeding of phthisical and
insane patients, and the artificial feeding of those with gastric
fistulæ (performed on account of stricture of the œsophagus) to
be explained?” I will introduce my answer by a very unexpected
pronouncement relative to the assertion that mechanical stimulation of
the stomach wall by food constitutes a reliable and effective means
of calling forth the secretory work of the glands. This assertion,
which is so categorically set forth in many text-books of physiology,
and which consequently has gained hold of the mind of the physician,
is nothing else than a sad misconception degenerated into a stubborn
prejudice. My own statement, repeated in many published articles, and
at the meetings of various medical societies, that this dictum is only
a picture of the imagination, has met, for the most part, either with
an unbelieving shake of the head or else with a direct avowal that “it
cannot be so.” I regret exceedingly that these steadfast unbelievers
are not here, so that we might together bring the matter before the
tribunal of fact, to the demonstration of which we will now proceed. To
this matter I attribute very great importance. It is on this ground,
according to my opinion, that the whole battle must be fought out
between the generally accepted view that every agency is capable of
exciting the gastric mucous membrane and the theory that it is only
excitable by specific and selected stimuli. If once the defenders of
the old opinion are driven from their position and obliged to admit
the inefficiency of mechanical stimulation, there would be nothing
further left for them than to build up new theories and search out
old facts concerning gland work which have hitherto been rigidly kept
in the shade. We may take it that it is mainly because people were so
seized with the belief in the direct and simple mechanical explanation
that Bidder and Schmidt’s experiment of the excitation of gastric
secretion by mental effect has been so little taken into consideration,
notwithstanding that it appeared so thoroughly reliable and convincing.

I will now repeat the experiment of mechanical stimulation of the
gastric mucous membrane before you in the well-known, traditional,
and classic manner. Here is a dog with a gastric fistula on which
a cervical œsophagotomy has in addition been performed. I open the
fistula; as you see, nothing flows out of the stomach; it was washed
out clean with water an hour ago. We take the celebrated feather and
also a tolerably strong glass rod. Folds of blotting-paper saturated
with red and blue tincture of litmus are placed at hand. I now ask my
assistant to continuously move the feather and glass rod, alternately,
in all possible directions in the stomach, changing from one to the
other every five minutes. On removal from the stomach each is carefully
dried with red and blue blotting-paper. You have all seen, gentlemen,
that this procedure has now been kept up for half an hour. From the
fistular orifice not even a single drop has escaped, and, moreover, the
drops of moisture on all the pieces of red blotting-paper I have been
able to hand to you have assumed a distinct blue tinge, caused by the
moisture of the alkaline mucous membrane. The blue pieces, however,
have merely been made wet without altering their colour. Consequently,
with the most thorough mechanical stimulation of the whole cavity of
the stomach, we have not been able to find a single spot possessing a
noticeable acid reaction. Where, then, are the streams of pure gastric
juice of which we read in text-books! What objection can be raised
against the conclusiveness of this experiment? In my opinion only one:
that we are dealing with a dog out of health, whose gastric glands from
some possible cause are unable to react normally. This single objection
can be set aside before your eyes. After failing with the mechanical
stimulation, we proceed forthwith to the sham feeding of the same
animal. The dog takes the food offered it with keen appetite, and you
see that, exactly five minutes after beginning the feeding, the first
drops of juice appear from the stomach, followed by others faster and
faster. I catch a couple of drops on the blue litmus paper, and you see
that they produce bright red specks on the blue sheet. After thirty
minutes' sham feeding we have collected 150 c.c. of juice, which,
without filtering, looks as clear and transparent as water.

We cannot, therefore, possibly doubt that, when the proper stimulus is
used, the gastric glands react to it in a perfectly normal fashion,
furnishing a healthy gastric juice. From this it irrefutably follows
that only one explanation is to be found for the negative result in
the first half of our experiment, viz., that the mucous membrane
of the stomach, so far as secretory activity goes, is perfectly
indifferent to mechanical excitation. And yet this mechanical stimulus
is demonstrated as an exciting agency in the physiological lecture
theatre. I venture to think that this lecture experiment from now
onwards will quit the field, and give place to the one I have just
shown you. This apparently simple experiment of mechanical stimulation
can, however, only be successfully performed when certain very obvious
rules are followed. These, however, physiologists have not observed,
probably on account of a preconceived belief in the effectiveness of
the mechanical stimulus. These rules are two. First, it is necessary
that the stomach should be clean, and that nothing shall gain entry
to it from without. Such conditions were not formerly fulfilled. It
is true the stomach was emptied by removing the stopper from the
fistular cannula, but it was not washed out till an acid reaction
was no longer given, and consequently preformed gastric juice was
left behind between the folds of the mucous membrane. At the same
time saliva from the cavity of the mouth could gain entry, which
quickly became acidified in the incompletely emptied and imperfectly
washed-out organ. It is, therefore, not surprising that the glass
tube, by setting up contractions of the stomach, was the means of
expressing small quantities of acid fluid from the fistula-tube. (The
relationship between mechanical stimulation and the motor functions
of the stomach is not to be confounded with what we are here speaking
of.) That matters are as I state, and that the facts correspond to
the explanation is proved by this; namely, that nobody till now
has obtained genuinely pure gastric juice of an acidity amounting
to 0.5 or 0.6 per cent. It is only necessary to call to mind that
Heidenhain, when determining the acidity of the juice first obtained
from the resected stomach, was placed in no little doubt as to whether
his results (0.5 to 0.6) were correct, and his assistant at the
time (Gscheidlen) was set to verify the correctness of his standard
solutions. The acidity of the “purest” juice known at that time was
scarcely 0.3 per cent. As a further proof that none of the older
observers ever really obtained a secretion from mechanical stimulation
pure and simple, we may adduce the fact that none of them made mention
of the constant and precise period of five minutes' latency. To
overlook this was not possible if a genuine excitation of the glands
had been obtained.

Of no less importance is the second condition when we wish to perform
the experiment of mechanical stimulation in the correct way. It is
very necessary that the gastric glands be not already in activity at
the beginning of the experiment, and also that during the experiment
no impulse comes into play, which of itself, apart from mechanical
excitation, could excite the glands to secretion. Nor have we any
proof that observers formerly waited for hours before commencing
the experiment and convinced themselves that the gastric glands had
ceased working. On the contrary, we have not the slightest evidence to
indicate that the authors had attempted to guard against accidental
psychical stimulation of the glands--a matter which we have seen is of
considerable difficulty. And some dogs are so easily excited in this
way that it is almost impossible to bring their glands to rest, or at
least it is necessary to wait for hours. The experimenter must strain
his whole attention to preserve such an experiment free from objection.
It is only necessary that some food be near the dog, or that the hands
of the attendant who has prepared the food should smell of it, or that
some other similar circumstance should come into play, and the glass
tube, quite undeservedly, will be made answerable for the excitation of
the gastric glands. As you have just seen, both of our conditions have
been fulfilled on the dog before you, and the result of the experiment
stands in irreconcilable contradiction to those of the laboratory and
lecture experiment of former times.

The importance of the experiment, which I have already dwelt upon,
justifies me in making still further demands upon your attention in
order to show you two modifications of it. Nobody has as yet said, with
regard to mechanical stimulation, that in order to obtain results the
mechanical agency must simultaneously come into contact with numerous
points of the inner surface of the stomach. But in order to meet this
possible objection I will now show you two new modifications. Again
a similar dog is used, that is to say, one on which both gastrotomy
and œsophagotomy have been performed. The stomach has been washed out
clean and is at present in a state of complete rest. Into the fistula
I bring a thick glass tube containing a number of small openings (2
to 3 mm. diameter) at its rounded end. The other end of the tube is
connected with a glass ball containing tolerably coarse sand. Leading
into the ball is a second tube, with which an india-rubber pump can be
connected and a blast of sand blown through. By rhythmic compression
of the india-rubber ball I inject sand with considerable force into
the stomach, and this play is kept up for ten to fifteen minutes;
nevertheless, we see no trace of gastric juice. The sand falls out
again between the side of the cannula and the glass tube, and it
is either dry or scarcely moistened, but in no case is it able to
turn blue litmus red. And yet we are here dealing with a strong and
widely diffused stimulus. Look for a moment at the performance of the
bellows outside the stomach. From every opening of the tube--numbering
considerably more than ten--a strong stream of sand is ejected. If you
hold your hand against it, you feel quite distinctly that the grains
of sand strike with considerable force. And now, when our experiment
is ended, we may convince ourselves by sham feeding, in easy and
unquestionable fashion, that the innervation of the dog’s stomach is
perfectly normal.

Yet another experiment on a similar dog. Into its empty and resting
stomach an india-rubber ball is introduced. This is distended with
air by means of a syringe till it is as large as a child’s head and
maintained in this condition for a time, afterwards being allowed
to collapse. The procedure is kept up for ten to fifteen minutes.
During this time not a single drop of juice has appeared from the
stomach. The surface of the ball taken out of the organ is everywhere
alkaline. And here also subsequent sham feeding shows that the dog is
in a suitable condition for the experiment. I must add that in making
this observation the dog must not be too hungry, that is to say, must
have been fed within ten to twelve hours before, otherwise a psychic
excitation of the secretion can readily be induced.

If one dispassionately regards this question, and if any of our methods
for the study of gastric secretion are reliable, one must be convinced
step by step in the laboratory of the uselessness of mechanical
stimulation. In the case of dogs with an ordinary gastric fistula, and
failing some special reason, not a drop of gastric juice ever escapes
from the stomach other than during the digestive period. How could
this be the case if the mechanical stimulus were effective, since the
inner rim of the fistula-tube is continuously in contact with the
gastric mucous membrane? The same holds good for the dog with resected
stomach. During the experiment a glass or india-rubber tube is brought
sufficiently far into the _cul-de-sac_ to catch the juice, and yet not
a drop flows through the tube, nor does its inner surface ever become
acid, so long as true secretory conditions are absent. Moreover, the
tube has tolerably often to be taken out and set right.

In the ordinary gastric fistula in dogs, when the operation has lasted
a long time--over a year--folds of mucous membrane are often formed
in the neighbourhood of its inner orifice which completely close the
tube. In these cases a long, thick, perforated metal tube has to be
passed in deeply, and yet the manipulation of itself never calls forth
a secretion. Further, it is a daily occurrence to find in the stomach
of the dog thick rolls of hair, and yet their presence in no way
hinders the arrest of the secretion, which occurs when digestion has
ceased. Such an occurrence would have been specially obvious in our dog
with the isolated stomach, since it was bedded with sawdust in order
to guard against maceration of the wound by juice trickling out. Very
often we found enormous quantities of sawdust in the stomach, as much
as half a pound weight; obviously the dog had licked the wound from
adherent sawdust, which it then swallowed, together with that sticking
to its nose. And yet these particles of sawdust of themselves, which
certainly acted as mechanical stimuli, never caused a secretion. It
appears to me that this long series of facts ought to suffice to carry
the supposition to its grave that by direct mechanical stimulation
one is able to set the neuro-secretory apparatus of the stomach into
activity.

And yet the feather and the glass tube continue the even tenor of
their ways to this moment and function in some text-books, yea, even
in articles which specially treat of gastric secretion as exciters of
the gastric glands. There are, it is true, a few physiologists who
hold mechanical stimulation, in relation to gastric secretion, not to
be very effective, and give it a subordinate position in the series of
exciting agencies, but as yet I know of no other physiologist who has
wholly denied its influence, and who has not held it possible to obtain
at least some juice by it.

To conclude this lecture, we will take into consideration a question
connected with the matter we have just discussed. Since the contact of
food with the gastric mucous membrane has no direct influence on the
secretion, is its entry into the stomach devoid of all connection with
the secretory process?

It can hardly be doubted that, under normal conditions, the stomach is
the seat of certain definite sensations, that is to say, its surface
has a certain degree of tactile sensibility. This sensation is, as a
rule, very weak, and the majority of people become accustomed to pay
no heed to it in the normal course of digestion. They obtain their
sensations of general well-being, and especially of satisfaction
from the enjoyment of food, without taking cognisance of the factors
contributing to them. The feeling of general hunger, however, is
referred solely to the stomach.

On the other hand, all of us have met with men who could describe
exactly, and with gusto, how they were able to follow a special
tit-bit, or a mouthful of a favourite wine, the whole way through the
œsophagus down to the stomach, especially when the latter happened
to be empty. Naturally the gourmand, who directs his attention
continuously to the act of eating, can in the end distinctly perceive
sensations, and even call them up to the consciousness, which in other
people are normally masked by other sensations and impressions. We may
therefore take it that the satisfaction derived from eating is caused
not only by stimulation of the mouth and throat, but also by impulses
awakened by the passage of the food along the deeper portions of the
œsophagus and by its entry into the stomach. In other words, food which
merely passes through the mouth and throat produces less enjoyment
and excites, therefore, a less feeling of appetite than the food
which passes the whole way into the stomach. The appetite, the eager
craving after food, is, indeed, a very complex sensation, and often
not merely the need of the organism for food material is necessary for
its excitement, but also a condition of thorough well-being, together
with a normal healthy feeling in all parts of the digestive tract. For
this reason it is easy to understand how patients who have diseased
sensations in these organs, and who have no feeling of appetite,
no desire for food, remember the sensations, whether consciously or
unconsciously, even when they are no longer present. Cases are known
to neuro-pathologists where people with gastric anæsthesia suffered
from this loss of appetite. Such patients are no longer conscious of
having stomachs, and dislike the idea of eating because the food, as
they express it, appears to fall into a strange empty sack. In this
way one can also conceive how the appetite becomes lost in cases of
long-continued obstruction of the alimentary tube. The patients forget
their stomachs, and in such instances direct introduction of food into
the organ, after an operation, may suddenly bring back the appetite.

As a further illustration, I may be permitted to give an instance from
my own personal experience. After an illness with which a transient but
high fever was associated, although otherwise fully recovered, I had
lost all desire for food. There was something curious in this complete
indifference towards eating. Perfectly well, I only differed from
others in that I could with ease abstain from all food. Fearing that I
should collapse, I resolved on the second or third day to endeavour to
create an appetite by swallowing a mouthful of wine. I felt it quite
distinctly pass along the œsophagus into the stomach, and literally at
that moment perceived the onset of a strong appetite. This observation
teaches that the tactile sensation of the stomach at the moment of
entry of food is capable of awakening or increasing the appetite. It is
known that withholding food from the organism, or in other words the
creation of a necessity for food, does not lead immediately, nor in
all cases, to the production of an appetite, to a passionate craving
for food. How often does it happen that the ordinary hour for a meal
has struck, and yet, owing to some keenly interesting occupation, not
the least desire for food is felt? It is known to everybody, indeed it
has become a proverb, that real appetite first sets in with eating.
If this be true, the initial impulse towards awakening an appetite
may originate in the stomach and not in the buccal cavity. When we
spoke above of the desire for food being the excitant of the secretory
nerves of the stomach, we naturally meant the passionate and conscious
longing for food, that which is called “appetite,” and not the latent
need of the organism for nourishment, the lack of nutrition, which
has not yet been transformed into a concrete passionate desire. A
good example which enables us to differentiate between these two
factors is furnished by our dogs with sham feeding. The necessity for
food exists in such cases even before the experiment; the juice,
however, only begins to flow as soon as this need has taken the form
of a passionate longing. It is therefore quite possible that in the
case of some dogs, and at a certain stage of hunger, the touching of
the gastric mucous membrane with any object at hand, its mechanical
excitation, its distension by the food mass, may give the impulse which
excites the appetite, and when the appetite is awakened the juice
flows. This is possibly a third reason why, in the old experiment,
the mechanical stimulus came to be considered effective. Viewed from
this point it may, to a certain degree, lead to a reconciliation
between my assertion concerning the inefficiency of the mechanical
stimulus and the generally prevailing belief. I further also admit that
mechanical excitation will at times call into play the work of the
gastric glands, not however directly by means of a simple physiological
reflex, but indirectly, after it has first awakened and enlivened the
idea of food in the dog’s consciousness, and thereby called forth the
passionate desire. I hope that the foregoing will in no way lead to a
confusion of ideas in your minds, but will assist you to an exact and
concrete analysis of the previous simple explanation of the facts. This
representation, which bears more or less of a hypothetical character,
could, of course, be submitted to experimental proof. For such it is
only necessary to compare the influence which sham feeding exercises
in an œsophagotomised dog with that in one having a simple gastric
fistula.

LECTURE VIII

PHYSIOLOGICAL ACTION AND THE TEACHING OF INSTINCT: EXPERIENCES OF THE
PHYSICIAN

It would be desirable, in the interests of medicine, that the methods
described in these lectures should be employed in experimental
investigations into the pathology and therapeutics of the digestive
canal on the lines laid down--The fact that the beginning of the
secretory work in the stomach depends upon a psychic effect harmonises
with the experiences of every-day life, namely, that food should
be eaten with attention and relish--To restore the appetite has
from all ages been the endeavour of the physician--The indifference
of the present-day physician towards appetite--Probable causes of
this--Curative remedies based upon a restoration of appetite--The
therapeutic effects of bitters depend upon the excitation of
appetite--The usages of the mid-day meal are in agreement with
physiological requirements--Physiological reasons for certain
instinctive customs and empirical regulations--Importance of an
acid reaction of the food--Dietetics of fat and its therapeutic
application--The peculiar position of milk among food-stuffs is
based on physiological reasons--Explanation of the curative effects
of sodium bicarbonate and sodium chloride--The causes of individual
differences in the work of the digestive glands--Participation of
the inhibitory nerves of secretion in the production of pathological
effects.

GENTLEMEN,--To-day we shall endeavour to bring the previously
communicated results of our laboratory investigations into
reconciliation with the customs observed in the ingestion of food,
and with the regulations prescribed by the physician in disorders of
the digestive apparatus. To bring our knowledge to full fruition, and
so secure for it the most useful application, the same methods should
be applied from the same standpoint to the experimental investigation
of the pathology and therapeutics of the alimentary canal. Nor should
we be likely to encounter insuperable difficulties. Thanks to the
advances of bacteriology, many of the pathological processes can now
be experimentally produced in the laboratory. Moreover, we would,
in a sense, have to deal with external ailments, since our present
methods enable us to obtain access to any desired part of the inner
surface of the digestive canal. In such pathological animals the
functional diseases of the apparatus could be studied in a precise
and detailed manner; that is to say, the alterations of secretory
activity, the properties of the fluids, and the conditions under which
they appear could be examined. On such animals therapeutic remedies
could also be tested, the whole process of healing and the final result
experimentally observed, while the conditions of secretory activity
during every phase of the healing process could be investigated. It can
hardly be doubted that scientific, that is to say ideal, medicine,
can only take its proper position as a science when, in addition to an
Experimental Physiology and Pathology, there has also been built up an
Experimental Therapeutics. A proof that this is possible is furnished
by the recent vigorous strides made by the science of bacteriology.

I have already described one of such pathological therapeutic
experiments; namely, on the dog whose vagi nerves were divided in the
neck. Other similar cases I can also call to mind. Our dog with the
two stomachs suffered at one time from a slight and transitory gastric
catarrh. It was then very interesting to observe that the pathological
process (which we were usually able to wholly guard against) spread
from the large to the small stomach. It manifested itself here in
an almost continuous slimy secretion of very slight acidity, but of
strong digestive power. At the beginning of the ailment, indeed before
it became fully established, the psychic stimulation was remarkably
effective (that is to say, still furnished juice in appropriate
quantity), while local excitants almost completely failed. One may
conceive that the deeper layers of the mucous membrane with the gastric
glands were still healthy, and thus easily thrown into activity by
central impulses, whilst the surface of the membrane with the end
apparatus of the centripetal nerves was already distinctly damaged.
I mention these, which I may call impressions rather than precise
observations, because I wish to point out what a fruitful field awaits
the investigator who wishes to study, with the aid of our present
methods, the pathological conditions of the digestive organs and their
treatment. Such an investigation is all the more desirable because
clinical study of the same subject (notwithstanding the zeal devoted to
it during the last ten years and the results derived therefrom) has to
contend with serious difficulties. We must not forget that the sound or
stomach-tube, the chief clinical instrument, is more uncomfortable than
the ordinary form of gastric fistula which was previously practised on
animals, and yet the physiology of the stomach, even with the aid of
the latter, made no material progress for many long years. Nor is this
difficult to understand. The investigator obtained through the fistula
a mixture of substances from which it was difficult, or even at times
impossible, to decide anything.

Hence the exact scientific study of therapeutic questions in this
region still belongs to the future. But this does not exclude the
probability that the newer acquirements of physiology may fruitfully
influence the work of the physician. But physiology naturally can make
no pretence to guide the field of medicine, since the knowledge at its
disposal is incomplete and is much more restricted than that of the
broad world of clinical reality. As a recompense for this, however,
physiological knowledge is often able to explain the causation of an
illness and the meaning of empirical curative methods. To employ a
remedy the mode of action of which is not clear is quite a different
thing from knowing precisely what we are doing. In the latter case
the treatment of the diseased organ will be more effective because it
will be better adapted to the special needs of the case. It is thus
that medicine, being daily enriched by new physiological facts, will
at length grow into what it ideally must become; namely, the art of
repairing the damaged machinery of the human body, based upon _exact_
knowledge, or, in other words, applied physiology.

We may now return to our subject. If it be at all admitted that human
instinct is the outcome of an every-day experience, which has led to
the unconscious adoption of the most favourable conditions for life,
it is particularly so with regard to the phenomena of digestion. The
expression that physiology merely confirms the precepts of instinct
is justified here more than anywhere else. It appears to me also
that, in relation to the foregoing facts, instinct has often made
out a brilliant case when brought before the tribunal of physiology.
Perhaps the old and empirical requirement, that food should be eaten
with interest and enjoyment, is the most imperatively emphasised and
strengthened of all. In every land the act of eating is connected
with certain customs designed to distract from the business of daily
life. A suitable time of day is chosen, a company of relatives,
acquaintances, or comrades assemble. Certain preparations are carried
out (in England a change of raiment is usually effected, and often a
blessing is asked upon the meal by the oldest of the family). In the
case of the well-to-do a special room for meals is set apart, musical
and other guests are invited to while away the time at meals--in a
word, everything is directed to take away the thoughts from the cares
of daily life, and to concentrate them on the repast. From this point
of view it is also plain why heated discussions and serious readings
are held to be unsuitable during meal-times. Probably this also
explains the use of alcoholic beverages at meals, for alcohol, even
in the lighter phases of its action, induces a mild narcosis, which
contributes towards distraction from the pressing burden of the daily
work. Naturally this highly developed hygiene of eating is only found
in the intelligent and well-to-do classes, first, because here the
mental activity is more strained and the various questions of life more
burning; and secondly, because here also the food is served in greater
quantity than is required for the wants of the organism. In the case of
the poorer classes, where mental activity is less highly developed, the
greater amount of muscular activity and the constant lack of more than
sufficient nourishment insure a strong and lively desire for food in a
normal manner, without recourse to any special regulations or customs.
The same conditions explain why the preparation of food is so choice
in the case of the upper classes and so simple in that of the lower.
Further, all the accessories of the meal, which are foretastes of the
actual repast, are obviously designed to awaken the curiosity and
interest, and to augment the desire for food. How often do we see that
a person who begins his customary meal with indifference afterwards
enjoys it with obvious pleasure when his taste has been awakened by
something piquant or, as we say, appetising. It was here only necessary
to give an impulse to the organs of taste, that is, to excite them, in
order that their activity might be later maintained by less powerful
excitants, for a person who feels hungry such extra inducements are,
of course, not necessary. The quelling of hunger in his case affords of
itself sufficient enjoyment. It is not, therefore, without reason that
it is often said that “Hunger is the best sauce.” This dictum, however,
is only right up to a certain point, for some degree of appetising
taste is desired by everybody, even by animals. Thus, a dog which has
not fasted for more than some hours will not eat everything with equal
pleasure which dogs usually eat, but will seek out the food which it
relishes best. Hence the presence of a certain kind of spice is a
general requirement, although naturally individual tastes differ.

This short discussion as to how different people behave with regard
to the act of eating is of itself testimony that care should ever be
taken to keep alive the attention and interest for food and to promote
enjoyment of the repast--that is to say, that care should be taken of
the appetite. Every one knows that a normal, useful food is a food
eaten with appetite, with perceptible enjoyment. Every other form of
eating, eating to order or from conviction, soon becomes worse than
useless, and the instinct strives against it. One of the most frequent
requests addressed to the physician is to restore the appetite. Medical
men of all times and of every land have held it to be a pressing
duty, after overcoming the fundamental illnesses of their patients, to
pay special attention to the restoration of the appetite. I believe
that in this they are not only animated by an endeavour to free their
patients from troublesome symptoms, but also by the conviction that
the return of appetite of itself will favour the restitution of normal
digestive conditions. It may be said that to the same extent to which
the patient wishes back his appetite the physician has effectively
employed measures to restore it. Hence we have not a few remedies which
are specially named “gastric tonics,” and whose action is to promote
appetite. Unfortunately medical science has latterly deviated from
this, the correct treatment of the appetite, and that which corresponds
to the real conditions. If one reads current text-books on disorders of
digestion, it is remarkable how little attention is paid to appetite
as a symptom or to its special therapy. Only in a few of them is its
importance indicated, and then merely in short, parenthetic phrases.
On the other hand, one may meet statements in which the physician is
recommended to adopt no special means for counteracting so unimportant
a subjective symptom as a bad appetite! After what I have said and
demonstrated to you in these lectures, one can only designate such
views as gross misconceptions. If anywhere, it is precisely here
that symptomatic treatment is essential. When the physician finds it
necessary, in disorders of digestion, to promote secretory activity by
different remedies, this object can most certainly and completely be
achieved by endeavouring to restore the appetite. We have already seen
that no other excitant of gastric secretion, so far as quantity and
quality of the juice are concerned, can compare with the passionate
craving for food.

To a certain degree we can understand--and this contributes to an
explanation of matters--how medical science of our time has come
to regard so lightly the loss of appetite as a special object for
treatment. Now, however, the experimental method has penetrated more
and more into medical science, with the result that many pathological
factors and therapeutic agents are judged of according to whether they
hold good in the laboratory or not--that is to say, they are valued
only in so far as they can be verified by laboratory experiments.
Naturally we do not doubt that a movement in this direction indicates
a great advance, but even here, as with every undertaking of mankind,
things do not proceed without mistakes and exaggerations. We must not
consider an event to be a mere picture of the imagination because
it is not realisable under given experimental conditions. We often
do not know all the essential conditions for the production of the
phenomenon in question, nor are we yet able to grasp the connection
between all the separate functions of life as fully as may be desired.
Thus in the clinical treatment and pathology of digestion assistance
was sought for in the laboratory, but nothing was there met with which
had a relation to appetite, and consequently this factor was overlooked
in medical practice. As stated above, the psychic gastric juice
obtained only cursory mention in physiology, and this not even by all
authors; and when it was noticed it was related more as a curiosity.
Great importance was, on the other hand, assigned to the mechanical
stimulus, the efficiency of which, now that our knowledge is more
complete, has been shown to be purely imaginary. Each of the contending
factors has at length been assigned its proper place, and if clinical
medicine maintains her worthy desire of following out the experimental
investigation of her problems, she must in actual practice accord to
appetite its old claim for consideration and treatment.

But notwithstanding the indifference of physicians to appetite in
itself, many therapeutic measures are based on the promotion of it.
And in this the truth of empiricism makes itself irresistibly felt.
When the patient is enjoined to eat sparingly, or when he is restrained
from eating at all till the physician expressly permits, or again, when
he is (for instance, during convalescence) removed from his ordinary
surroundings and sent to an establishment where the whole life, and
particularly the eating, is regulated according to physiological
needs--in all these cases the physician seeks to awaken appetite, and
relies upon it as a factor in the cure. In the first case, where the
food is prescribed in small portions, in addition to preventing the
overfilling of a weak stomach, the oft-recurrence of appetite juice,
which is so rich in quantity and so strong in digestive power, is of
great importance. I ask you here to call to mind one of our experiments
in which food was given in small portions to a dog, and thus led to
a secretion of much stronger juice than if the whole ration had been
eaten at once. This was an exact experimental reproduction of the
customary treatment of a weak stomach. And such a regulation of diet
is all the more necessary, since, in the commonest disorders of the
stomach, only the surface layers of the mucous membrane are affected.
It may, consequently, happen that the sensory surface of the stomach,
which should take up the stimulus of the chemical excitant, is not
able to fulfil its duty, and the period of chemical secretion, which
ordinarily lasts for a long time, is for the most part disturbed, or
even wholly absent. A strong psychic excitation, a keen feeling of
appetite, may evoke the secretory impulse in the central nervous system
and send it unhindered to the glands which lie in the deeper as yet
unaffected layers of the mucous membrane.

An instance of this, taken from the pathological material of the
laboratory, I have already related at the beginning of this lecture. It
is obvious in these cases that the indication is to promote digestion
by exciting a flow of appetite juice, and not to rely upon that excited
by chemical stimuli. From this point of view the meaning of removing
a patient, the subject of chronic weakness of the stomach, from his
customary surroundings is also plain. Take, for instance, a mentally
overstrained individual, or a responsible official; how often does
it happen that he cannot for a moment distract his thoughts from his
daily work. He eats without noticing it, or eats and carries on his
work at the same time. This often happens, particularly in the case of
people who live in the midst of the incessant turmoil of great cities.
The systematic inattention to the act of eating prepares the way for
digestive disturbances in the near future, with all their consequences.
There is no appetite juice, no “igniting juice,” or, at most, very
little. The secretory activity comes slowly into play; the food remains
much longer in the digestive canal than is necessary, or passes, for
want of sufficient digestive juices, into a state of decomposition
which irritates the mucous membrane of the alimentary canal and brings
it into a condition of disease. No medicinal treatment can help
such a patient while he remains surrounded by his old conditions.
The fundamental cause of his illness still continues in progress.
There is only one course to pursue; namely, to take him completely
away, to free him from his occupation, to interrupt the interminable
train of thought, and to substitute for a time, as his only object
in life, the care of his health, and a regard for what he eats. This
is attained by sending the patient to travel, or by placing him in a
hydropathic establishment. It is the duty of the physician to regulate
not only the life of individual patients according to such rules,
but also to have a care that in wider circles of the community a due
conception of the importance of eating should be disseminated. This
is particularly so with the Russian physician. It is precisely in the
so-called intelligent classes of Russians that a proper conception
of life generally is often found wanting, and where an absolutely
unphysiological indifference towards eating often exists. More
methodical nations, like the English, have made a species of cult of
the art of eating. It is, of course, degrading to indulge excessively
and exclusively in culinary enjoyments, but, on the other hand, a lofty
contempt for eating is also reprehensible. As so often is the case, the
best course here also lies between the two extremes.

With the establishment of mental effect upon the secretion of juice the
influence of condiments enters upon a new phase. The conclusion had
already been empirically arrived at that it was not alone sufficient
for the food to be composed exclusively of nutrient substances, but
that it should also be tasty. Now, however, we know why this is so.
For this reason the physician, who has often to express an opinion
upon the suitability of the dietaries of different persons, or even
of whole communities, should constantly bear in mind the question of
psychic secretion; that is to say, he should inquire after and learn
how the food has been eaten, whether with or without enjoyment. But how
often do the people who have charge of the commissariat pay attention
solely to the nutritive value of the food, or place a higher value on
everything else than taste? We must, further, in the interest of the
public weal, direct attention especially to the feeding of children.
If this or that inclination of the taste ultimately determines the
relation of grown-up individuals towards food, a matter with which
the commencing phase of digestion is closely linked, it would seem
undesirable to habituate children solely to a nicety and uniformity of
gustatory sensations. Such might effect their capabilities of adapting
themselves to other conditions in after life.

The question of the therapeutic influence of the so-called bitters,
it appears to me, bears the closest connection with that of appetite.
After a long period of high repute these substances have been almost
expelled from the list of pharmaceutic remedies. When tested in
the laboratory, they were unable to justify their old and valued
reputation; when directly introduced into the stomach, many of them
were unable to produce a flow of gastric juice. Consequently, in the
eyes of the clinician, they became greatly discredited, so that many
were quite ready to discard their use altogether. Obviously, the simple
conclusion was drawn that a weak digestion could only be assisted by
a remedy which directly excites secretory activity. In this, however,
it was forgotten that the conditions of the experiment possibly had
not corresponded with the actual state of affairs. The whole question
of the therapeutic importance of the bitters, however, acquires a
different significance when we link it with another question, such, for
instance, as how do bitters affect the appetite? It is the universal
opinion of the earlier and later physicians that bitters increase
the appetite, and if this be so everything is said. They are, in
consequence, real secretory stimulants, since the appetite, as has many
times been repeated in these lectures, is the strongest of all stimuli
to the digestive glands. It is, however, not by any means strange
that this had not previously been observed in the laboratory. The
substances were either introduced directly into the stomachs of normal
dogs or else injected into the circulation. But their action is chiefly
bound up with their effect upon the gustatory nerves, and it was not,
therefore, without some reason that this large group of remedies,
consisting of substances of the most varied chemical composition, were
grouped together mainly on account of a certain bitter taste common
to them all. A person who suffers from digestive disturbance has,
moreover, a blunted taste, a certain degree of gustatory indifference.
The ordinary foods, which are agreeable to other people, and also to
himself when in health, now appear tasteless. They not only arouse no
desire for eating, but may even cause a feeling of dislike; there
is no sense of taste, or at best a perverse one. It is necessary,
therefore, that the gustatory apparatus should receive a strong
stimulus in order to restore a normal sensation. As experience teaches,
this object is most quickly attained by exciting sharp, unpleasant,
gustatory impressions, which by contrast awaken the idea of pleasant
ones. In either case there is no longer indifference, and this is the
foundation upon which an appetite for this or that kind of food may
be awakened, and here a general physiological law is illustrated. The
light appears brighter after darkness, a sound louder after silence,
the enjoyment of blithesome health more intense after illness, and so
on. This explanation of the appetising effects of bitters proceeding
from the mouth does not exclude the possibility of some such similar
influence coming also from the stomach. As has been already stated in
the fifth lecture, there is some reason for believing that certain
impulses from the cavity of the stomach are likewise necessary for
the excitation of appetite. It is possible that bitters not only act
directly on the gustatory nerves in the mouth, but that they also act
on the mucous membrane of the stomach in such a way that sensations
are generated which contribute to the passionate craving for food. As
a matter of fact, it has been confirmed by many clinicians that after
the administration of bitters some such special sensations do arise
in the stomach. The effect of these remedies consists, therefore, not
merely in the generation of a simple reflex, but in the production of
a certain psychic effect, which indirectly excites a physiological
secretory activity. The same probably applies to other substances, such
as condiments. In any case, whether our explanation corresponds to the
actuality or not, the question of the therapeutic effect of bitters
is settled in the affirmative the moment we acknowledge that these
substances awaken appetite. The problem, therefore, of an experimental
investigation of bitters consists in establishing the fact that they
have an effect upon the appetite. The question is a difficult one,
and has not hitherto been attempted in the laboratory. It is not
sufficient to hand over clinical observations to the laboratory as
experimental proofs. One must have, in addition, the assurance that the
investigation has been correctly carried out; that is to say, that it
dealt exactly with the point under consideration. It is interesting to
observe that the connection between appetite and gastric juice is by
many physicians, and in many text-books of medicine, exactly reversed.
Thus it is represented that some medicinal remedy calls forth a
secretion of gastric juice, and this, by its presence in the stomach,
awakens an appetite. Here we have to deal with a false explanation of
a true fact, and that because it was not recognised that a psychic
effect could by any possibility be a powerful excitant of secretory
nerves. The customs of the chief meal of the day also correspond with
our physiological results. After this or that _hors d’œuvre_, perhaps
also with a liqueur of brandy (especially customary in Russia), both of
which are designed to awaken the appetite, the repast proper begins,
and, in the majority of cases, with something hot, consisting mostly of
meat broth (_bouillon_, different soups, and so on). After this comes
the really nourishing food--meat of different kinds served in various
ways, or, in the case of poorer people, stews made with vegetables,
and therefore rich in carbohydrate material. This sequence of foods,
from the standpoint of physiology, is quite rational. Meat broth, as
we have already seen, is an important chemical excitant of gastric
secretion. An attempt is therefore made in two ways to secure a free
secretion of gastric juice to act on the chief food; first, in the
excitement of the appetite juice by the _hors d’œuvre_, and secondly,
in the promotion of the flow by the action of the meat broth. It is in
this way that human instinct has made provisions for the digestion of
the chief meal. A good meat broth can only be afforded by well-to-do
people, and consequently with the poorer classes a less expensive,
and, indeed, also a less effective, chemical excitant is used for
awakening the early secretion. For example, _kwas_[31] serves in this
way with the Russian population, while in Germany, where the price
of meat is high, different kinds of soups are used, consisting of
water mixed with flour, bread, etc. It is further to be borne in mind
that the quantity of the digestive juices in general stands in close
connection with the content of water in the organism. This has been
shown by the experiments of Dr. Walther for the pancreatic juice, and
by my own for the gastric juice. If this sequence of foods, therefore,
holds good for healthy people, it must be even more strictly adhered
to in pathological conditions. Thus, when a person has no appetite,
or only a weak one, he has no psychic juice or only very little;
consequently, the meal must in every case be begun with a strong
chemical excitant--for example, with a solution of the extractives of
flesh. Otherwise solid foods, particularly if they do not consist of
meat, would remain long in the stomach without any digestion whatever.
It is, therefore, in every way desirable to prescribe meat juice,
strong broth, or meat extract to people who have no appetite. The same
applies also to forced feeding, for instance, of the insane. It is true
that the method of introduction in this case necessarily secures the
presence of a chemical excitant, since the food can only be introduced
in a fluid form. In any case the addition of meat extract would be very
useful. If one arranged the ordinary fluid foods in descending order,
according to the influence of the chemical excitants, the following
would be the series: first, the preparations of the flesh, such as meat
juice and the like; secondly, milk; thirdly, water.

The usual termination of the repast is also, from the physiological
standpoint, easy to be understood. The chief meal is generally ended
with something sweet, and everybody knows that sweets are pleasant.
The meaning of this is easy to guess. The repast, begun with pleasure,
consequent on the pressing need for food, must also, notwithstanding
the stilling of hunger, be terminated with an agreeable sensation. At
the same time the digestive canal must not be burdened with work at
this stage; it is only the gustatory nerves which should be agreeably
excited. After thus dealing in general with the usual arrangement of
our meals, we may now speak of some special points.

Above all comes the acid reaction of the food. It is apparent that
acidity enjoys a special preference in the human taste. We use quite
a number of acid substances. Thus, for example, one of the commonest
seasoning substances is vinegar, which figures in a number of sauces
and such like. Further, many kinds of wine have a somewhat acid
taste. In Russia, _kwas_, especially in the acid form, is consumed in
great quantities. Moreover, acid fruits and green vegetables are used
as food, and they are either of themselves acid, or made so in the
preparation. In medicine this instinct is likewise often made use of,
and acid solutions, especially of hydrochloric and phosphoric acids,
are prescribed in digestive disturbances. Finally, Nature itself
constantly endeavours to prepare lactic acid in the stomach in addition
to the hydrochloric acid. The former arises from the food introduced,
and is consequently always present. These facts are all physiologically
comprehensible when we know that an acid reaction is not only necessary
for an efficient action of the peptic ferment, but is at the same time
the strongest excitant of the pancreatic gland. It is even conceivable
that in certain cases the whole digestion may depend upon the
stimulating properties of acids, since the pancreatic juice exerts a
ferment action upon all the constituents of the food. In this way acids
may either assist digestion in the stomach where too little gastric
juice is present, or bring about vicarious digestion by the pancreas
where it is wholly absent. It is easy, therefore, to understand why the
Russian peasant enjoys his _kwas_ with bread. The enormous quantity
of starch which he consumes, either as bread or porridge, demands a
greater activity upon the part of the pancreatic gland, and this is
directly brought about by the acid. Further, in certain affections of
the stomach, associated with loss of appetite, we make use of acids,
both from instinct as well as medical direction, the explanation being
that they excite an increased activity of the pancreatic gland, and
thus supplement the weak action of the stomach. It appears to me that a
knowledge of the special relations of acids to the pancreas ought to be
very useful in medicine, since it brings the gland--a digestive organ
at once so powerful and so difficult of access--under the control of
the physician. We could, for instance, intentionally discard digestion
in the stomach, and thus transfer it to the bowel, by prescribing
substances which do not excite the gastric glands. On the other hand,
by lessening the acidity of the gastric juice we could reduce the
activity of the pancreas, and these are matters which might be made use
of in various special diseases, or even in some general disturbances of
the digestive apparatus.

No less instructive is a comparison of the results of our experiments
upon fat, with the demands of instinct and also with the precepts of
dietetics and therapeutics. Everybody knows that fatty foods are heavy,
that is, difficult of digestion, and in the case of weak stomachs
they are usually avoided. We are now in a position to understand this
physiologically. The existence of fat in large quantities in the chyme
restrains in its own interest the further secretion of gastric juice,
and thus impedes the digestion of proteid substances; consequently, a
combination of fat and proteid-holding foods is particularly difficult
to digest, and can only be borne by those who have good stomachs
and keen appetites. The combination of bread and butter is less
difficult, as might _a priori_ be inferred from its wide employment.
Bread requires for itself, especially when calculated per unit, but
little gastric juice and but little acid, while the fat which excites
the pancreatic gland insures a rich production of ferment both for
itself and also for the starch and proteid of bread. Fat alone does
not count by any means as a heavy food, as may be seen from the fact
that large quantities of lard are consumed in certain districts of
Russia with impunity. This also is comprehensible, since the inhibitory
influence of the fat in this case does not prevent the digestion of
any other food-stuff, and is conducive to the assimilation of the
fat itself. There is no struggle in this case between the several
food constituents, and therefore no one of them suffers. In harmony
also with daily experience the physician, in cases of weakness of the
stomach, totally excludes fatty food and recommends meat of a fat-free
kind; for example, game, etc. In pathological cases, however, where an
excessive activity of the gastric glands is manifested, fatty food,
or fat as emulsion, is prescribed. And here medicine has empirically
brought to its aid the restraining action of fat, which we have so
strikingly seen in our experiments.

Amongst all the articles of human food, milk takes a special position,
and this is unanimously recognised, both in daily experience and in the
practice of medicine. By everybody milk is considered a light food,
and is given in cases of weak digestion as well as in a whole series
of severe illnesses; for example, in heart and kidney affections. The
extreme importance of this substance, a food prepared by Nature itself,
we can now well understand. There are three properties of milk which
secure it an exceptional position. As we already know, in comparison
with nitrogenous equivalents of other foods, the weakest gastric juice
and the smallest quantity of pancreatic fluid are poured out on milk;
consequently, the secretory activity requisite for its assimilation is
much less than with any other food-stuff. In addition, milk possesses
a further important property. Thus, when it is introduced unobserved
into the stomach of an animal it causes a secretion both in the stomach
and also one from the pancreas; consequently, it appears to be an
independent chemical excitant of the digestive canal; and in this
action it is remarkable that we perceive no essential difference in
the effect when the milk is brought unnoticed into the stomach from
that which occurs when it is given to the animal to lap. Although
flesh is a better chemical excitant, it is by no means a matter of
indifference how it gets into the stomach. It must, therefore, be
accepted that milk excites not only a really effective, but at the same
time a very economic, secretion, and also that the appetite is unable
to stimulate this secretion into a more active or abundant flow. The
secret of the relation of milk to the secretion of the digestive juices
can, unfortunately, at present be submitted to no further analysis or
investigation. We are at liberty, however, to suppose that the fat on
the one hand is of importance for the inhibition of the gastric glands,
and the alkalinity on the other for the restraint of the pancreas. Thus
the gastric glands and the pancreas, notwithstanding the presence of
excitants, are maintained by milk at a certain but not too high degree
of activity, a matter which is in every way desirable in consideration
of the easy digestibility of its constituents. Finally, the third
characteristic which is observed to belong to milk, and which is
probably only an expression of the first, consists in the following.
When one administers to an animal equivalent quantities of nitrogen, in
the one case as milk, in the other as bread, and afterwards estimates
the hourly output of nitrogen in the urine, it results that the
increase during the first seven to ten hours after the milk (compared
with the excretion beforehand) amounts only to from 12 per cent to 15
per cent of the nitrogen taken in, while after bread it amounts to 50
per cent. If the hourly rate of absorption and the extent to which
milk and bread are respectively used up be taken into consideration,
it has to be admitted that these augmentations of urinary nitrogen
which appear soon after feeding must be expressions of the functional
activity of the digestive canal itself, and that this activity in the
case of bread is three or four times greater than in the case of milk
(_Experiments of Prof. Rjasanzew_); consequently, in the case of milk
a much larger fraction of its nitrogen is free to be used up by the
organism at large (irrespective of the organs of digestion) than in
that of any other kind of food. In other words, the price which the
organism pays for the nitrogen of milk, in the form of work on the part
of its digestive apparatus, is much less than that for other foods. How
admirably, therefore, the food prepared by Nature distinguishes itself
when compared with all others!

The facts just related bring forward a new aspect from which the
relative nutritive values of different foods may be judged. The older
criteria must frankly make room for the new or else be displaced by
them. Experiments upon the utilisation of food-stuffs, in which what
remains undigested is determined as well as what is absorbed into
the body fluids, cannot alone be trusted to solve the question in a
satisfactory manner. Suppose, for instance, that in the digestion of
a given food the alimentary canal has been given a certain work to
perform; if it be in health the work will be accomplished in the
best possible manner--that is to say, with complete abstraction of
everything nutrient. You will thus learn how much nutrient material was
contained in the food, but the question of its digestibility remains
as obscure as before. In your experiment you do not know how great an
effort it has cost the alimentary canal to extract all the nourishment
from the food. Nor can artificial digestion experiments settle the
question of digestibility, for experiments in which food is normally
partaken of are quite different from those in the test-tube, where
we have to deal with only one juice, and not with the interaction of
different juices and different food constituents. That one must here,
as a matter of fact, make a distinction is clear from the observation
of Dr. Walther in our laboratory. Fibrin, which is regarded by all as
the most easily digested proteid, proved, when compared with a nitrogen
equivalent of milk, to be a much stronger excitant of the pancreas,
although milk contains, in addition to nitrogenous substances, a good
deal of other non-nitrogenous material. The digestibility and nutritive
value of foods must obviously be decided by an estimation of the real
work which they entail upon the digestive apparatus, both in regard to
the quantity and quality of the juices poured out on a given amount
of nutrient material. The energy used up in gland metabolism must be
deducted from that of food taken in. The remainder will then indicate
the value of the food to the organism; that is to say, will give the
amount available for use by all the other organs exclusive of the
digestive apparatus. From this point of view those materials must be
taken as less nourishing and less digestible which are in large part
used up to make good the expenditure entailed by their digestion on
the part of the alimentary canal; that is to say, those food-stuffs
are less useful whose nutritive value little more than covers the cost
of their digestion; consequently, it is of great practical importance
to compare from this aspect the same foods differently prepared--for
example, boiled and roast meat, hard and soft boiled eggs, boiled and
unboiled milk, etc.

A discussion of some further medical questions may here be taken up.
The first concerns the therapeutic use of the neutral and alkaline
salts of sodium. In clinical, pharmacological, and physiological
text-books it is stated now, as ever, that these salts promote a flow
of gastric juice. We may look in vain, however, for any experimental
foundation to support this doctrine. The experiments brought forward
cannot be regarded as conclusive. When Blondlot sprinkled sodium
bicarbonate upon flesh, or Braun and Grützner introduced sodium
chloride solutions directly into the blood, they began with methods
either false in themselves or far removed from normal conditions. In
this case, however, the gaps in the experiment were happily made good
by the clinician, for the experiment appeared to be confirmatory of
clinical experience. That sodium salts (the chloride and bicarbonate)
are useful in disorders of the digestive apparatus there can be no
doubt. How do they act, however? It appears to me that here, as in
some other cases, medical science has fallen into error. When we
know that an effect takes place it does not by any means imply that
we know the mechanism by which it occurs; and although medicine is
broad enough and comprehensive enough to make free use of empiricism
in practice, yet it often thinks in narrow grooves when it turns to
the explanation of facts. It frequently tries to explain complicated
healing processes in the simplest way, on supposed physiological
data. And this is true in the present case, which affords an example
of prevalent medical reasoning; the alkalies work favourably in
digestive disturbances--therefore they are succagogues. Naturally
the stomach, under the influence of alkalies, sometimes begins to
secrete a greater quantity of juice. This means, however, that it
has recovered from a disordered state and has returned to normal
conditions. Consequently, the effect is due to the fact of recovery,
and not to a direct influence of the alkalies. This latter, however,
must be specially proved. The assistance afforded by the alkalies to
the organism might be capable of another explanation; for example,
that which is ordinarily given. In this case, however, I venture to
offer a reason for the effects of sodium chloride, and of the alkaline
salts of sodium, which is exactly the opposite of that generally
accepted. We were unable to convince ourselves of any succagogue
influence on the part of these salts. Indeed, both on the stomach
and pancreas they proved in our hands to have an inhibitory effect.
In addition to the experiments which I previously brought forward
concerning the relation of alkalies to gastric and pancreatic juice,
I may relate the following observation. A dog which fortunately had
survived the performance, one after the other, of a gastric fistula,
a pancreatic fistula, and an œsophagotomy, received daily during the
course of several weeks an addition of soda to its food. The animal
enjoyed good health and had an excellent appetite. When the first sham
feeding experiment was carried out, the relatively small effect of
this otherwise very active juice-exciting procedure at once struck
us. At the same time we observed that the pieces of flesh which fell
from the upper end of the œsophagus, contrary to the ordinary rule,
were hardly at all insalivated. In this dog, therefore, a greatly
lowered activity of several digestive glands--viz., of the gastric,
pancreatic, and salivary glands--simultaneously existed. With regard
to the salivary glands the circumstance was naturally submitted to
closer investigation. I believe that the inhibitory influence of the
alkalies on the digestive glands, which was here proved experimentally,
may furnish a basis for the following representation of their mode
of action in producing healing effects. Catarrhal affections of
the stomach are characterised by an incessant or very protracted
secretion of slimy, weakly acid gastric juice. Further, in many cases
the affection begins with a hypersecretion, that is an abnormal
excitability, of the secretory apparatus which makes itself evident in
a superfluous and useless flow. The same must be conceived to happen
in disorders of the pancreatic gland; at least such a condition sets
in after operations performed for physiological purposes. It is,
further, justifiable to suppose that, when an affection is once set
up by this or that cause, it may later maintain itself independently;
for continuous activity has undoubtedly a harmful influence on the
glands. The due nourishment, and the restoration of organs after
activity, proceeds best during rest. In the normal course of events,
after a period of active work follows a pause, during which the
latent work of restoration is accomplished. When, therefore, a remedy
effectively restrains the excessive work of a diseased organ, it may
in this way contribute to the removal of the pathological condition,
and thus to a restoration of the normal state. In this consists, in my
opinion, the healing effects of the alkalies. One might draw a parallel
between the action of these substances in digestive disturbances
and that of digitalis in compensatory disturbances of the heart. An
uncompensated heart beats rapidly, and thereby only aggravates its
condition. Its time of rest, that is of recovery, of restitution of
the organ, is shortened. A vicious cycle is set up. The weak action
of the heart lowers blood pressure; the lowering of this leads (from
known physiological causes) to an increase in the number of beats;
the quickening leads to weakening of the organ. Without doubt the
digitalis aids by breaking through this vicious cycle, in that it
greatly slows the pulse, and thereby gives new power to the heart. With
our explanation of the action of the alkalies harmonises the further
circumstance that, with the use of the salts in question, a strict diet
is generally prescribed, which means that a certain amount of rest is
secured for the digestive glands. It is interesting that in clinical
investigations with the stomach-tube, after a period when the alkalies
were looked upon as succagogues, a new phase has also set in, mention
being now more frequently made of a restraining effect.

The cause of the erroneous belief that alkalies promote a flow of juice
obviously lies in this, that people omitted to compare the effects
of the saline solutions with those of like quantities of water (_Dr.
Chigin_).

The second point which we may consider is the following. The chief
difficulty of the physician who wishes to regulate the diet of patients
when they suffer from digestive disturbances consists in the fact
that idiosyncrasy plays a very important _rôle_. In one and the same
illness, different patients react to the same diet in wholly different
ways. That which is agreeable to one, and is well borne and useful,
may be rank poison to another. Consequently, the golden rule in
dietetics is to give no directions with regard to food till one has
made inquiries concerning the inclinations and habits of the patient.
What does all this indicate? Till now physiology had no experimental
answer to the question. But our facts, it appears to me, contribute
to a clearing up of the situation. Every food determines a certain
amount of digestive work, and when a given dietary is long continued,
definite and fixed types of glands are set up which can only slowly
and with difficulty be altered. In consequence, digestive disturbances
are often instituted if a change be suddenly made from one dietetic
_régime_ to another, especially from a sparse to a rich diet; such, for
instance, as happens after the long Russian fasts. These disturbances
are expressions of the temporary insufficiency of the digestive glands
to meet the new demands made upon them.

Finally, it may be of some use to relate the following here. There
are often cases of sudden and unaccountable digestive disturbances.
From the standpoint of modern physiology they might be explained by
an activity of the secreto-inhibitory nervous system, which from some
cause or other has been excessively and abnormally stimulated. In any
case this system is now a factor of which the physician has to take due
account.

SWALLOWING AND MOVEMENTS OF THE STOMACH AND INTESTINES

BY W. B. CANNON, M.D.

_Of the Physiological Laboratory of the Harvard Medical School Boston,
Mass., U. S. A._

[NOTE.--In the beginning of 1896 Dr. Professor Henry Pickering
Bowditch, one of our Board of Scientific Assessors in the Nutrition
Case suggested the use of the Röntgen ray as a means of learning more
than was then known about the mechanism of swallowing. There was
much difference of opinion among research physiologists about this
important function, and the question was far from settled. Magendie
published a theory of deglutition, in Paris, in 1836, which was
practically accepted until 1876, when Dr. Professor Angelo Mosso, of
the University of Turin, Turin, Italy, established the theory of sole
peristaltic assistance in swallowing. Again in 1880 Dr. Professor
Kronecker, of Berne, Switzerland, in connection with Dr. Falk, and
later in connection with Dr. Meltzer, of New York, produced evidence
to prove a more complicated process in deglutition than that of
peristalsis alone. But even Kronecker and Meltzer found, as they went
on, evidence to modify their earlier beliefs, and hence the subject
was not cleared up to a point of general agreement.

The suggestion made by Dr. Bowditch was taken up in the Harvard
Physiological Laboratory and formed the beginning of a series of
studies of the mechanical factors in digestion. The reports of these
studies, presented by Dr. W. B. Cannon and collaborators, in the
_American Journal of Physiology_, in the volumes of 1898 and 1903,
are so understandable, even to the layman ignorant of physiological
nomenclature, that we are prompted to give them, almost entire,
leaving out only the technical description of the methods employed,
which are only interesting to research students who have access to the
_Journal_.

It will be noted that three of the professors of physiology
mentioned in connection with this preliminary study of the nutrition
problem--Bowditch, Mosso, and Kronecker--are members of our presently
organised Board.—HORACE FLETCHER.]

THE MOVEMENTS OF THE FOOD IN THE ŒSOPHAGUS

BY W. B. CANNON AND A. MOSER

_From the Laboratory of Physiology in the Harvard Medical School_

Extracts from _American Journal of Physiology_, 1898

The movements of deglutition, in common with many other physiological
processes, were explained by the older physiologists on anatomical
grounds. Thus, Magendie divided the act into three parts, corresponding
to the anatomical regions of the mouth, pharynx, and œsophagus. The
muscles of each of these divisions were considered the active agents
in propelling the food onward. The function of moving the mass to the
pharynx was variously ascribed to the tongue itself, to the mylohyoid
muscles, and to gravity. For the second part, the movement through the
pharynx, there was more unanimity of opinion, since the constrictors,
especially the middle and lower, were evidently concerned.

Direct observations on the movement of swallowed masses in the
œsophagus were first made by Mosso. The œsophagus of a dog was laid
bare, and a transverse incision made through it, or a piece of it
excised. A small wooden ball was placed in the canal below the excised
part, and the animal was then stimulated to swallow. One or two seconds
after the contraction of the pharyngeal muscles a peristaltic wave
began to traverse the œsophagus. This wave did not stop at the point of
excision, but in due time reappeared below, and carried the ball to the
stomach. Thus the act was shown to be controlled by the central nervous
system. Peristalsis was so plainly the motive power that the action was
never doubted. Yet this belief was soon to be questioned.

In 1880 Falk and Kronecker studied the movements in the mouth and
pharynx, and advanced the theory that deglutition was accomplished by
the rapid contraction of the muscles of the mouth. During the act of
swallowing the air-tight buccal cavity shows a manometric pressure of
twenty centimetres of water. The same pressure was demonstrated to be
present also in the œsophagus, but not in the stomach. This pressure
was considered sufficient to force food through the œsophagus before
the peristaltic wave traversed it. Another argument for rapid descent
was found in the fact that cold water can be felt in the epigastric
region almost immediately after being swallowed. Further, when strong
acids pass through the gullet, they corrode but small parts of it, and
not the entire mucous membrane, as would be the case were the acid
carried to the stomach by peristalsis.

Over a year and a half ago it was suggested by Prof. H. P. Bowditch
that if some substance opaque to the Röntgen rays were swallowed,
it could be seen in its passage to the stomach, and the nature of
its movement thus determined. Anæsthesia could be dispensed with,--a
desirable condition, since observers had found that it interfered
greatly with the deglutition reflex. It would be unnecessary to open
either the abdominal or the pleural cavity. The reflex stimulus of
food, moreover, would be better than electrical stimulation of the
superior laryngeal nerve. In short, the animal would swallow normal
food under practically normal conditions. At Dr. Bowditch’s suggestion
and with his valuable assistance--which we gratefully acknowledge--we
made the following series of experiments.

To render the swallowed mass opaque, subnitrate of bismuth was used.
The salt is tasteless, practically inert, and can be fed in large
quantities without harm. In order that observations could be made by
more than one person, all experiments were conducted in a dark room. On
the side of the animal opposite the Crookes tube was placed an open
fluorescent screen, on which the different tissues of the animal were
outlined with varying degrees of light and shade. Among these shadows
the swallowed mass appeared as a darker object, and thus its motion
could be studied.

For the first experiments the goose was selected. The head and neck
were held stationary by a tall pasteboard collar, which allowed free
movement of the head without constriction of the neck. The fluorescent
screen was placed against this collar at a uniform distance of thirty
centimetres from the tube. When a bolus of corn-meal mush mixed with
bismuth was placed in the pharynx, it descended slowly and regularly,
and occupied about twelve seconds in passing over a distance of fifteen
centimetres. The screen was marked at intervals of two centimetres with
cross lines, by means of which the relative rate in different parts of
the œsophagus could be studied. A vibrator marking tenths of a second
was interrupted whenever the bolus crossed a line. An average of over
one hundred such observations showed that the rate became slightly
slower as the bolus proceeded.

In order to test liquids, molasses was mixed with bismuth to such a
consistency as to drop easily from a glass rod. When this was fed
with a pipette, it passed slowly and regularly down the œsophagus,
clearly by peristalsis. The rate was about the same as for solid food.
In both these experiments the addition of water would sometimes cause
irregularities in the descent. Microscopic sections from four different
parts of the œsophagus of the goose showed no histological difference.

In the experiments on the cat, the animal was placed on its back and
left side on a holder. The extremities were secured by straps. The
head was held between two upright rods, connected above by a thong;
this allowed free movement of the head, without resistance to the
passage of food. Shreds of meat dipped in bismuth were ordinarily
masticated and swallowed without difficulty. For soft solids, bread and
milk were used, so fluid as to be easily drawn up into a pipette. The
insolubility of the bismuth salt rendered the study of liquids more
difficult. Strong solutions of potassic iodide and other salts, and
suspension of bismuth, in acacia and molasses were tried; but a simple
mixture of milk and bismuth, shaken in a test tube and immediately
drawn up into a pipette, was found most practicable.

Inasmuch as the movement of these different foods varied in different
parts of the œsophagus, it will be convenient to divide the latter into
three sections. The first or cervical portion extends from the pharynx
to the thorax; the second or thoracic, from here to the lower half of
the heart; and the third comprises the rest of the canal. The relative
length of these three parts is about in the ratio of 9:8:6.

The beginning of deglutition was noted by one observer by a finger on
the larynx; the same observer called out when the bolus arrived at
the thorax, heart, and stomach respectively, while the other observer
noted the time. The movement of solids will first be considered. The
descent the entire way was by peristalsis, but the rapidity varied. The
duration of the movement in the cervical portion was two and a half
seconds, and in the thoracic region a little less than two seconds.
At the lower end of the heart there was sometimes a slight pause. In
the lower section, from the heart to the stomach, the movement was
decidedly different; the rate was always very slow. The distance was
less than one-third of the entire canal, yet the time consumed in this
part ranged from six to seven seconds, or three-fifths of the entire
time of descent. The character of the movement here was also peculiar.
Whereas in the upper sections the passage was uniform and regular, with
a slight acceleration in the thoracic region, here it was apparently
irregular, for the bolus descended about one centimetre with each
inspiratory movement of the diaphragm, and remained stationary or
descended very slightly during expiration. Thus a series of hitches
seemed to carry the bolus to the cardia. A probable explanation of this
peculiar movement is that the stomach and lower œsophagus were pulled
down with each descent of the diaphragm. This would make the movement
appear irregular, although it was really a slow peristalsis. It may be
well to remark here that this movement was invariably observed in the
cat with every kind of food.

Semi-solids, namely, a mush of bread and milk, descended in the same
way as solids; but the rate was slightly faster in the upper œsophagus,
for the bolus took about a second less to reach the cardiac level. From
here the rate was the same as with solids.

For liquids, one and a half to two seconds sufficed for the descent to
the midheart region. Here there often occurred a long pause, from a few
seconds to a minute or more. Then the œsophagus apparently contracted
above the liquid, which slowly passed on to the stomach, as already
described. Sometimes it seemed as if a swallowing movement, evidenced
by a rise of the larynx, started the peristaltic wave. Again, several
swallows would succeed one another before the liquid passed on. A few
times the bismuth and milk seemed strung out along the œsophagus;
some more liquid descending would gather this up, and the whole mass,
assuming an ovoid form, would move into the stomach.

Thus in the cat the total time for deglutition varies from nine to
twelve seconds. The lowest section presents no change ascribable to a
difference in consistency, while in the upper sections the rate does
slightly increase with the more liquid character of the food.

In experiments on the dog, bismuth enclosed in capsules or wrapped in
shreds of meat was fed as the solid. The general phenomena were as
follows: With the rise of the larynx there was a quick, propulsive
movement of the bolus, which descended rapidly for a few centimetres,
sometimes as far as the clavicle. From this point the rapidity
was diminished, yet no pause was observed; the bolus simply moved
more slowly. This rate was then continued to the stomach without a
slackening of speed in the diaphragmatic region, as was observed in the
cat. Semi-solids moved in the same way as solids. The total time of
descent from larynx to stomach was from four to five seconds.

Liquids gave even a more decided squirt in the beginning of the
movement. To render the œsophagus as lax and free as possible, the
head of the dog was released from the upright rods and held by the
hands after the food was placed in the mouth. Sometimes the liquid
descended rather rapidly as far as the heart, at other times no further
than the clavicle; then without a pause it passed on slowly and
regularly, reaching the stomach in about the same time as solids and
semi-solids.

Thus in the dog and cat but little variation was seen in the swallowing
of liquids and solids. The liquids pass somewhat faster in the upper
œsophagus. But in some animals the difference of rate with foods of
varying consistency is much more marked. In the horse, for instance,
mere observation shows a decided variation in the rate of movement
in the œsophagus. Liquids shoot along the gullet, while solids move
clearly by peristalsis. To determine the rate of solids, one hand was
placed on the larynx of a horse to note the beginning of swallowing,
and the other hand near the shoulders, where the bolus could be easily
felt in its passage. The time consumed by the bolus in passing over a
certain distance was measured by a stop watch. The rate obtained for
solids, such as hay or grain, was from thirty-five to forty centimetres
a second.

For semi-solids, a mixture of bran and water was made, thin enough to
run easily between the fingers. Each bolus was watched by a separate
observer with a separate watch. The average rate obtained was the same
as for solids.

Liquids in the horse pass with a rapidity too great to be affected
by peristalsis. Another force must be sought. Among the various
muscles supposed to be effectual in moving food into the pharynx, the
mylohyoids were shown by Meltzer to be essential. The styloglossi were
cut by him without much interference with deglutition, but section of
the mylohyoid nerves rendered the act impossible. The activity of these
muscles in the horse during swallowing is easily perceived by the hand.
Their energetic contraction is a sufficient explanation of the rapid
passage of water through the œsophagus. The motion here is more than
five times as rapid as that of solids and semi-solids.

Meltzer’s experiment to measure the rate of liquids in man by
passing a stomach tube containing litmus paper was repeated by us
with some modifications. Congo red paper was used, since it is more
sensitive than litmus; it also furnishes a means of differentiating
between mineral and organic acids, as the discolouration produced
on Congo red by mineral acids is removed by ether. It was thus
possible to distinguish between the discolouration produced by
gastric regurgitation and that produced by the swallowed liquid. For
the swallowed liquid, one-half per cent lactic acid was found most
satisfactory, as the colour produced by it on Congo red test paper is
almost instantly discharged in ether. By this method the paper was
found discoloured within half a second after the rise of the larynx,
certainly too short a period for a peristaltic wave to carry the liquid
to the neighbourhood of the cardia.

The X-ray method lends itself less successfully to the study of
deglutition in man than in the other animals we have studied. The
thickness of the thorax, the distance of the œsophagus from the
surface, and the relation to dense tissues render the observation of a
swallowed mass difficult, especially when the mass is in rather rapid
motion. The few observations which we have to report were made on a
seven-year-old girl, placed in the sitting posture. Gelatine capsules
containing bismuth were used for solids, and were traced to a point
below the heart. The motion was very regular, and apparently due to
peristalsis, for the bolus descended without a hitch or irregularity of
any kind. Sometimes the capsule became fixed in the upper œsophagus,
at about the level of the second rib. Repeated swallows of water would
fail to dislodge it. An interesting point was noted here. With each
attempt at swallowing, the capsule would rise slightly, as if the
œsophagus was pulled up with the rise of the larynx; then the capsule
would descend to its former position.

Semi-solids--a mush of bread and milk--could be seen about as far as
solids; that is, to just below the heart. The motion of the mushy bolus
was the same as with solids, except that the rapidity was perhaps
slightly greater.

It should be noted here that with the human subject, as well as with
the horse, our results for semi-solids differ from those derived by
Meltzer’s method; for according to his statements semi-solids, like
liquids, are squirted down the œsophagus, and are not propelled by
peristalsis, as has been the case in our observations.

Liquids--bismuth and water--were seen only in the neck and upper
thorax. Here there was a decided squirt. With the rise of the larynx
the liquid was seen to pass rapidly through the pharynx and well down
into the thoracic œsophagus before it was lost to observation. The
rate, however, by estimation was less than that of liquids in the horse.

There remains to be considered Meltzer’s latest investigation, in
which he endeavoured to ascertain whether liquids remain above the
cardia till the arrival of the peristalsis, or ooze down before. An
experimental answer was secured by Meltzer by the following method. The
abdominal and gastric walls of an anæsthetised dog were incised, and a
tube (vaginal speculum) introduced. Through this the entrance of food
into the stomach could be observed directly. In repeated experiments no
liquid was seen to pass through the cardia before the arrival of the
peristaltic wave. An incision through the diaphragm near its anterior
origin showed that the swallowed liquid was not squirted as far as a
point an inch above the diaphragm. To observe the œsophagus nearer its
beginning, the upper three ribs were resected on the left side. Thus
the swallowed liquid was seen to shoot along the œsophagus before any
peristalsis reached this point. The resection of the fifth rib exposed
the œsophagus half-way between the bifurcation of the trachea and the
diaphragm. Here a bulging was sometimes observed immediately after
the beginning of the act, and the swallowed mass remained there until
a peristaltic wave carried it down. If the mass swallowed was small,
or was projected with moderate force, it might not even reach as far
as the bifurcation. From these experiments Meltzer concluded that in
animals, as in man, liquid food is not carried down the œsophagus by
peristalsis, but is thrown rapidly into a deep part of the canal. The
depth reached depends on the quantity swallowed, the force used, and
the tonicity of the lower part of the œsophagus.

The difference between these methods of Meltzer and those employed in
our experiments has already been mentioned; and merely his results,
which were obtained with liquids alone, need be considered here.
According to our observations on the dog, there was no distinct pause
at any part of the canal. The movement simply became slower, and
continued at this rate until the stomach was reached. Neither was
the rate through the diaphragmatic part of the œsophagus slower than
through the thoracic. The quick propulsive movement noticed in the
dog was observed with solids and semi-solids as well as with liquids,
but the liquids descended further down the canal before the movement
changed to the slower peristalsis. While this difference was evident to
the eye, the total time consumed by liquids in passing from pharynx to
stomach was not enough shorter than the time for solids and semi-solids
to be determined by our measurements.

SUMMARY.

The phenomena of œsophageal deglutition as determined by our
experiments may then be described as follows:—

There is a difference in swallowing according to the animal and the
food which is used.

In fowls the rate is slow and the movement always peristaltic, without
regard to consistency. A squirt-movement with liquids is manifestly
impossible, as the parts forming the mouth are too hard and rigid. With
this diminution of propulsive power in the mouth there is observed a
greater reliance on the force of gravity. The head is raised each time
after the mouth is filled, and the fluid by its own weight trickles
into the œsophagus, through which it is carried by peristalsis.

In the cat the movement is always peristaltic, and slightly faster than
in fowls. A bolus takes from nine to twelve seconds in reaching the
stomach. Liquids move somewhat more rapidly than semi-solids in the
upper œsophagus. In the lower or diaphragmatic part the rate is very
much slower than above, and is the same for liquids as for solids.

In the dog the total time for the descent of a bolus is from four
to five seconds. The food is always propelled rapidly in the upper
œsophagus, and moves more slowly below. This rapid movement is
frequently continued further with liquid food. No distinct pause was
observed when the movement of the bolus changed from the rapid to the
slower rate.

In man and the horse liquids are propelled deep into the œsophagus at a
rate of several feet a second by the rapid contraction of the mylohyoid
muscles. Solids and semi-solids are slowly carried through the entire
œsophagus by peristalsis alone.

THE MOVEMENTS OF THE STOMACH STUDIED BY MEANS OF THE RÖNTGEN RAYS

BY W. B. CANNON, M.D.

_From the Laboratory of Physiology in the Harvard Medical School_

Extracts from _American Journal of Physiology_, 1898

Since the stomach gives no obvious external sign of its workings,
investigators of gastric movements have hitherto been obliged to
confine their studies to pathological subjects or to animals subjected
to serious operative interference. Observations made under these
necessarily abnormal conditions have yielded a literature which is
full of conflicting statements and uncertain results. The only sure
conclusion to be drawn from this material is that when the stomach
receives food obscure peristaltic contractions are set going, which
in some way churn the food to a liquid chyme and force it into the
intestines. How imperfectly this describes the real workings of the
stomach will appear from the following account of the actions of the
organ studied by a new method. The mixing of a small quantity of
subnitrate of bismuth with the food allows not only the contractions
of the gastric wall, but also the movements of the gastric contents
to be seen with the Röntgen rays in the uninjured animal during normal
digestion. An unsuspected nicety of mechanical action and a surprising
sensitiveness to nervous conditions have thereby been disclosed.

INTRODUCTORY LITERATURE

The early writings on the subject of gastric movements are
characterised by general inferences from physical laws and from the
anatomical structure of the stomach. According to Galen the stomach
had four functions: to draw the food from the mouth (_facultas
attractrix_), to retain the food (_facultas retentrix_) during the
process of chemical digestion (_facultas alteratrix_), and, finally,
to pass the changed material onward (_facultas expultrix_). In later
writings the _facultas attractrix_ failed to appear as one of the
functions of the stomach. Fallopius, in the sixteenth century, changed
the notion of the _facultas retentrix_ by suggesting that the pylorus
alone performed this office, and that the muscles of the gastric wall
could help only by remaining quiet. Thus the _facultas alteratrix_ and
the _facultas expultrix_ are left as true gastric functions. It is with
the latter activity and its effects that this paper is concerned.

The ideas of the early writers concerning the pylorus and cardia are
of interest. The cardia, they were agreed, is closed during normal
digestion in order to keep the food from re-entering the œsophagus. The
pylorus they looked upon as the ruler of the actions of the stomach.
Such names as pylorus (keeper of the gate), janitor justus, and rector,
which the first investigators gave to the sphincter, indicate their
theories of its functions. The passage of chyme into the duodenum, the
keeping of undigested food in the stomach, the act of vomiting, were
all dependent, they believed, on the “will” of the pylorus.

No substantial advance was made beyond these hypotheses until the
beginning of the eighteenth century, when Wepfer and Schwartz applied
the experimental method to the study of the gastric movements and laid
the foundation of a more accurate knowledge. Wepfer vivisected wolves,
dogs, and cats, and observed constrictions following stimulation of
the stomach. He remarked a general contraction of the pyloric part in
vomiting and noted peristaltic and antiperistaltic movements passing
over the organ. About the middle of the stomach he frequently saw a
deep constriction. The investigations of Schwartz are more valuable in
that his search was for the normal action of the muscular coats. The
movements, as he observed them, were generally only slight. They began
either at the pylorus and passed to the left, half-way to the cardia,
or started at the fundus and went to the pylorus. The contractions
and relaxations, following one another, formed larger or smaller
depressions and elevations, _i. e._, more or less definite waves.

Near the middle of the last century Haller, after confirming the
results obtained by Schwartz and Wepfer, summarised his knowledge of
the motor functions of the stomach as follows. In general, contraction
alternates with relaxation, so that the stomach is, now here, now
there, made narrower by longitudinal or transverse depressions; then
in these same places relaxation and bulging occur. So long as both
apertures are closed the food is driven hither and thither by the
shifting movements. It first takes a definite direction when the cardia
or the pylorus opens. If the cardia opens, there is an antiperistalsis
followed by regurgitation and vomiting. If, on the contrary, the
pylorus relaxes, a contraction, starting at the œsophagus, pushes the
contents of the stomach into the duodenum. The pylorus allows the
passage of fluids, but if it be stimulated by over distention or by
hard pieces of food, it closes tightly.

Such was the knowledge of gastric movements in Haller’s time. A
comparison of his descriptions with those in any standard work on
physiology published ten or fifteen years ago will show that, despite
very many researches, little advance had been made. Examinations
of animals and men with gastric fistulas, studies of the stomach
through the atrophied abdominal wall, and vivisection have yielded
numerous results; but these have not been harmonious, and have led to
much controversy. Prominent in this mass of material as a valuable
contribution are Beaumont’s careful observations through the gastric
fistula of Alexis St. Martin. Beaumont’s work has recently been
confirmed by Hofmeister and Schütz, who, with Rossbach, Hirsch,
Openchowski, and others, have presented during the last twelve years
much new and interesting information. Since, however, it will conduce
to clearness to set forth the results of these investigations in
connection with my own work, their consideration will be deferred until
later.

It will then appear that these later investigations, like the earlier
researches, disagree as to the details of the stomach movements.
Such differences in results are the proper outcome of the abnormal
conditions under which the studies have been conducted. Obviously, in
order to see the natural movements of the stomach, the organ should be
observed in its natural state, and not after it has been disturbed by
removal from the abdomen, or by the adhesions and losses of substance
incident to gastric fistulas.

As a means of watching the gastric motor activities under normal
circumstances, Dr. H. P. Bowditch, in the autumn of 1896, suggested the
use of the Röntgen rays. The present paper is the result of the work
thus far completed. The kind assistance and stimulating counsel of Dr.
Bowditch throughout the investigation are gratefully acknowledged.

THE ANATOMY OF THE STOMACH AND ITS RELATIONS TO THE SHADOW

It must be constantly borne in mind that the shadows described in this
research are cast by the gastric contents, not by the stomach itself.
Therefore the movements of the organ are not seen directly, but are
indicated by their effect on the contained food. Variations in the
length and breadth of the stomach can be inferred from changes in the
outline of the shadow, but variations in the front-to-back diameter of
the organ must be judged from changes in the intensity of the shadow.

The form of the active stomach soon after food has been taken is shown
in outline in Figure 1. Since the several parts of the stomach are
to be mentioned frequently, it will be well to recall them here in
their relations to the outline. The larger, cardiac part of the organ
lies to the left of a line through _w x_. Into it the œsophagus opens
through the cardiac sphincter, or cardia, at _c_. The pyloric part,
which includes all of the stomach situated at the right of a line _w
x_, is closed by the pylorus at _p_. This part has two divisions: the
antrum at the right of the line _y z_, and the preantral part of the
pyloric portion, or middle region of the stomach, between the lines _w
x_ and _y z_. The lesser curvature corresponds approximately to the
anterior border of the shadow _c w p_; the greater curvature to the
more extensive sweep, _c p_, along the posterior border.

[Illustration: FIGURE 1.]

The wall of the cat’s stomach consists of three coats, but as this
paper deals only with the functions of the muscular coat, that alone
will be described. The gastric muscular fibres are disposed in three
sets: an outer longitudinal layer, a middle circular layer, and a set
of inner oblique fibres. The longitudinal fibres continue those of the
œsophagus, and, radiating over the cardiac end, become more marked
along the curvatures than on the front and back surfaces. Over the
antrum they lie in a thick, uniform layer. The circular fibres form a
complete investment, and are arranged in rings at right angles to the
curved axis of the stomach. Towards the pyloric end they become denser
and stronger, and at the pylorus form a thick bundle, the pyloric
sphincter. Separating the antrum from the rest of the stomach, at _y
z_, is a special thickening of the circular fibres, called by the
early writers the “transverse band,” and described by Hofmeister and
Schütz as the “sphincter antri pylorici.” The oblique fibres start
from the left of the cardiac orifice and pass as two strong bands
along the anterior part of the dorsal and ventral surfaces, giving off
fine fasciculi to the circular musculature; towards the antrum they
gradually disappear.

The musculature of the stomach consists of smooth muscle fibres,
the chief physiological characteristics of which are slowness of
contraction, rhythmic alternation of contraction and relaxation, and
a very great tonicity, or power of prolonged contraction. The action
of these muscles in the process of gastric digestion is now to be
considered.

THE NORMAL MOVEMENTS OF THE STOMACH

Since the time of Haller the chief contributors to the knowledge of the
mechanics of the stomach have been Beaumont, Hofmeister and Schütz, and
Rossbach.

Beaumont’s famous investigations on Alexis St. Martin are recorded in
almost all general works on physiology. Through a gastric fistula he
introduced a thermometer-tube and observed how it was affected by the
motions of the stomach. His conclusions are as follows: “The circular
or transverse muscles contract progressively from left to right. When
the impulse arrives at the _transverse band_, this is excited to a more
forcible contraction, and closing upon the alimentary matter and fluids
contained in the pyloric end, prevents their regurgitation. The muscles
of the pyloric end, now contracting upon the contents detained there,
separate and expel some portion of the chyme.... After the contractile
impulse is carried to the pyloric extremity, the circular band and all
the transverse muscles become relaxed, and a contraction commences in a
reversed direction, from right to left, and carries the contents again
to the splenic extremity to undergo similar revolutions.”

In close accord with Beaumont’s description of the activities of the
human stomach are the records of the investigations on the stomach
of dogs by Hofmeister and Schütz. They removed the stomach from the
body and placed it in a moist chamber, kept at body-heat and covered
with glass. Under such conditions the organ remained active for from
sixty to ninety minutes. A typical movement is described by these
observers as composed of two phases. In the first phase a constriction
of the circular fibres, deeper on the greater curvature, starts a
few centimetres from the cardia and passes towards the pylorus. As
the constriction proceeds it increases in strength until a maximum
is reached about two centimetres in front of the antrum. This
annular contraction, called by Hofmeister and Schütz the “preantral
constriction,” closes the first phase. Immediately thereafter the
strong sphincter antri pylorici, or transverse band, contracts. Now,
while the preantral constriction is relaxing, the sphincter antri
pylorici tightens still more, and the antrum is shut off from the rest
of the stomach. As soon as this has occurred a general contraction of
the muscles of the antrum follows. Relaxation begins at the sphincter
antri pylorici and progresses slowly towards the pylorus; it is
sometimes accompanied by an antiperistaltic movement.

Although Rossbach also used dogs, his results vary considerably from
those of Hofmeister and Schütz. This discrepancy is possibly accounted
for by a difference in method, for Rossbach left the stomach in the
body. The dogs were treated with morphia and curare, and the abdomen
was then widely opened, so that the movements could be clearly seen.
When the stomach was full Rossbach saw deep constrictions begin near
the middle and pass in waves to the pylorus. At first these movements
were weak; later, however, they became more vigorous. The fundus
remained in tonic contraction about its contents and took no part in
the peristalsis.

Before attempting to explain the difference in the records of these
observers I shall give an account of what may be seen in a cat by use
of bismuth subnitrate and the Röntgen rays.

1. _Movements of the pyloric part._--Within five minutes after a cat
has finished a meal of bread, there is visible near the duodenal end
of the antrum a slight annular contraction which moves peristaltically
to the pylorus; this is followed by several waves recurring at regular
intervals. Two or three minutes after the first movement is seen very
slight constrictions appear near the middle of the stomach, and
pressing deeper into the greater curvature, course slowly towards the
pyloric end. As new regions enter into constriction, the fibres just
previously contracted become relaxed, so that there is a true moving
wave, with a trough between two crests. When a wave swings round the
bend in the pyloric part the indentation made by it deepens; and as
digestion goes on the antrum elongates and the constrictions running
over it grow stronger, but until the stomach is nearly empty they do
not entirely divide the cavity. After the antrum has lengthened, a
wave takes about thirty-six seconds to move from the middle of the
stomach to the pylorus. At all periods of digestion the waves recur at
intervals of almost exactly ten seconds. So regular is this rhythm that
many times I have been able to determine within two or three seconds
when a minute had elapsed simply by counting six similar phases of the
undulations as they passed a given point. It results from this rhythm
that when one wave is just beginning several others are already running
in order before it. Between the rings of constriction the stomach is
bulged out, as shown in the various outlines in Figures 2, 3, 4, and 5.
The number of waves during a single period of digestion is larger than
might possibly at first be supposed. In a cat that finished eating
fifteen grams of bread at 10.52 A.M., the waves were running regularly
at 11.00 o’clock. The stomach was not free from food until 6.12 P.M.
During that time the cat was fastened to the holder at intervals of
half an hour, and the waves were always observed following one another
in slow and monotonous succession. At the rate of three hundred and
sixty an hour, approximately two thousand six hundred waves passed over
the antrum during that single digestive period.

From the above review it will be manifest that my observations of the
movements of the pyloric part agree closely with those of Rossbach,
but differ considerably from the harmonious results of the work of
Beaumont, and Hofmeister and Schütz. Beaumont’s methods, however, may
be justly criticised on the ground that the thermometer-tube which he
held in the stomach was wholly unlike food and very liable to bring
about unwonted contractions in so sensitive an organ as the stomach.
Further, the movements observed by Hofmeister and Schütz, as Ewald has
pointed out, may easily have resulted from the abnormal stimulus due
to lack of blood--a potent cause of peristalsis. And it will be shown
later that the accounts given by these investigators describe very well
the actions of the stomach when stimulated by an unusual irritant.
In this connection it may be added that since the publication of the
preliminary notice of my work, Roux and Balthazard, using the Röntgen
rays, have published the results of observations on the stomachs of the
dog and man similar to those thus far described in this paper.

The fact that my observations and those of Roux and Balthazard
were conducted under normal conditions, and that the conditions of
Rossbach’s experiments were more nearly normal than those of the other
observers mentioned, warrants the conclusion that the pyloric part has
a more important function than that of merely expelling the contents
of the stomach into the intestines. After summarising the description
given by Hofmeister and Schütz, Ewald, for _a priori_ reasons,
declares: “I cannot accept this view. The plain fact that the pyloric
portion secretes a strongly digesting fluid containing pepsin and
hydrochloric acid proves it to be an important part for the peptonising
function of the stomach.” The account of the remarkable manner in which
the pyloric portion performs this function must be deferred until the
movements of other parts of the stomach have been considered.

2. _Movements of the pyloric sphincter._--Rossbach mars his otherwise
careful work by declaring that the pylorus is tightly closed during
the whole digestive period of from four to eight hours, and that then
the sphincter relaxes and the peristaltic waves empty the stomach.
That this is not the normal action of the sphincter has been shown
by several observers. Hirsch watched dogs with duodenal fistulas and
saw food come from the stomach at intervals of one-fourth of a minute
to several minutes. Roux and Balthazard maintain that in dogs food
enters the duodenum at the completion of each wave of constriction.
Observations on the cat, however, do not support their view, but agree
rather with the statement of Hirsch.

In cats fed with bread mixed with subnitrate of bismuth, ten or
fifteen minutes elapse after the first constriction in the antrum
before any food can be seen in the duodenum. When food does appear
it is spurted through the pylorus and shoots along the intestine for
two or three centimetres. Not every constriction-wave forces food
from the antrum. On one occasion, about an hour after the movements
began, three consecutive waves were seen, each of which squirted food
into the duodenum. The pylorus remained closed against the next eight
waves, opened for the ninth, but closed once more against the tenth and
eleventh. For each of the four succeeding waves the sphincter relaxed,
but blocked the food brought by three constrictions that followed; and
in this irregular way the food continued passing from the stomach. Near
the end of gastric digestion, when the constrictions are very deep, it
may be that the pylorus opens for every wave.

When a hard bit of food reaches the pylorus, the sphincter closes
tightly and remains closed longer than when the food is soft. This
action of the sphincter was shown by giving with the regular food of
the cat a dry, hard pellet of equal parts of starch paste and bismuth
subnitrate about the size of a pea. The food itself contained merely
enough bismuth to throw a dim shadow, near the centre of which the
pellet could be clearly seen as a dark object. The continual passing of
the contraction-waves finally brought the little ball to the pylorus.
When it arrived there, five grams of bismuth subnitrate were introduced
into the stomach through a tube in the œsophagus. This was done in
order that the food passing into the intestines after the ball came to
the pylorus might be distinguished from that which had gone on before.
By kneading the stomach the bismuth was distributed, as shown by the
uniformly black shadow. The pellet could still be seen near the end of
the antrum when the constrictions passed over it. Now, although the
waves continued to run regularly, the very black food did not gather in
the intestines in sufficient amount to be recognised until forty-two
minutes after it had been introduced. And when, finally, the food did
show itself in the intestines, its shadow contrasted strongly with that
of the food which had already passed on. The slowness of the expulsion
is not to be regarded as wholly due to the hard mass. No doubt the
kneading of the stomach mixed the contents of different parts of the
organ and brought to the pylorus food not yet sufficiently digested
to be passed by that selective sphincter. But this does not explain
the whole delay. Food similar to that given here, except that it
contained no hard particles, has usually been seen as small masses in
the intestines within fifteen minutes after being swallowed. A part of
the delay was evidently, therefore, caused by the hard pellet. Further
evidence on this point was secured when, on one occasion, the sphincter
was seen to open only seven times in twenty minutes following the
arrival of a hard particle of food at the pylorus. The conclusion may
therefore be drawn that hard morsels keep the pylorus closed and hinder
the passage of the food into the duodenum.

3. _Activity of the cardiac portion._--The part played by the fundus
apparently has not hitherto been properly appreciated. It has been
regarded as the place for peptic digestion, or as a passive reservoir
for food; but it is in fact a most interestingly active reservoir.

[Illustration: FIGURE 2.]

[Illustration: FIGURE 3.]

[Illustration: FIGURE 4.]

[Illustration:
FIGURE 5.--Figures 2, 3, 4, and 5 present outlines of the shadow
of the contents of the stomach cast on a fluorescent screen by the
Röntgen rays. The drawings were made by tracing the outline of the
shadow on tissue paper laid upon the fluorescent surface, and are
about one-half the actual size. They show the change in the appearance
of the stomach at intervals for half an hour, from the time of eating
until the stomach is nearly empty.
]

The action of the cardiac portion will be best understood by comparing
the appearances the stomach presents at various stages in a digestive
period. In order to show these stages I carefully made a set of three
tracings of the outlines of the stomach as soon as possible after a
cat had finished eating, and another set of three every half hour
thereafter, until the contents had disappeared (Figs. 2, 3, 4, and
5). These tracings were made by placing white tissue paper over the
fluorescent screen, and drawing with a thick lead pencil, easily seen,
as much of the boundary of the stomach as I could at the end of each
expiration. Between the times for making the drawings the cat was
allowed to rest quietly on a mat, but care was taken to lay her in the
same position on the holder for every drawing. The drawings of each set
were afterwards fastened over one another, so that the lines coincided
as closely as possible. Another piece of tissue paper was then put over
these, and all four sheets were laid on an illuminated pane of glass.
It was thus easy to get a composite tracing which, considering the
movement imparted to the stomach by respiration, and the dimness of
the shadows in the later stages of digestion, probably represents more
exactly than any single drawing the outline of the stomach for each
successive period.

A comparison of these drawings shows that as digestion proceeds the
antrum appears gradually to elongate and acquire a greater capacity,
and that the constrictions make deeper indentations in it. But when the
fundus has lost most of its contents, the longitudinal and circular
fibres of the antrum contract to make it again shorter and smaller.
Its change of form, however, compared with the rest of the stomach, is
slight.

The first region to decrease markedly in size is the preantral part
of the pyloric portion. The peristaltic undulations, caused by the
circular fibres, start at the beginning of this portion, and gradually,
by their rhythmic recurrence, press some of the contents into the
antrum. As the process continues, the smooth muscle fibres with their
remarkable tonicity contract closely about the food that remains, so
that the middle region comes to have the shape of a tube (Figs. 3 and
4--1.30 P.M. to 2.30 P.M.), with the rounded fundus at one end and the
active antrum at the other. Along the tube very shallow constrictions
may be seen following one another to the pylorus.

At this juncture the longitudinal fibres which cover the fundus like
radiating fingers, and the circular and oblique fibres reaching in
all directions about this spherical region, begin to contract. Thus
the contents of the fundus are squeezed into the tubular portion.
This process, accompanied by a slight shortening of the tube, goes on
until the shadow cast by the fundus is almost wholly obliterated (Fig.
5--5.30 P.M.).

The waves of constriction moving along the tubular portion press the
food onward as fast as they receive it from the contracting fundus, and
when the fundus is at last emptied they sweep the contents of the tube
into the antrum (Fig. 5--5.00 P.M. to 6.00 P.M.). Here the operation is
continued by the deeper constrictions till, finally (in this instance
at 6.12 P.M.), with the exception of a slight trace of food in the
fundus, nothing is to be seen in the stomach at all.

The food in the fundus may possibly be slightly affected by the
to-and-fro movements of the diaphragm in respiration. With normal
breathing the upper border of the cardiac portion swings through about
one centimetre; with dyspnœa, or deep breathing, through one and a half
or two centimetres. Since the lower border does not move so much, the
contents are gently pressed, and then released from pressure, at each
respiration. The pyloric portion is moved very little by the diaphragm,
the oscillation being less than a half centimetre.

Moritz has pointed out the value of an organ like the stomach for
holding the bulk of the food and serving it out a little at a time, so
that the intestines may not become congested during their digestive and
absorptive processes. All of the advantages supposed to be thus secured
to the intestines may be claimed also for the stomach itself. For
the preceding description indicates, and experiments to be described
later prove, that the stomach is composed of two physiologically
distinct portions: the busy antrum, over which during digestion
constriction-waves are running in continuous rhythm; and the cardiac
part, which is an active reservoir, pressing out its contents a little
at a time as the antral mechanism is ready to receive them.

THE MOVEMENTS OF THE STOMACH IN VOMITING

The appearance of the stomach during vomiting has been studied
particularly by Openchowski. He says that when an emetic is given
there follows a quivering of the stomach-wall, which, beginning near
the pylorus, shows itself later in the antral and middle regions of
the stomach. The quivering afterwards passes into a contraction, most
strongly marked in the antral part, since the peristaltic waves running
down to the antrum from above are continually growing deeper. At the
same time the fundus expands spherically. The increased contraction in
the pyloric part drives the contents towards the more dilated portion,
and thence they are forced into the œsophagus by abdominal pressure.

The same phenomena occur when a cat is given apomorphine
hypodermatically. First the upper circular muscles relax and become so
flaccid that the slightest movement of the abdomen changes the form
of the fundus. Then there are apparently irregular twitchings of the
fundus wall. Soon a deep constriction starts about three centimetres
below the cardia and, growing in strength, moves towards the pylorus.
When it reaches the transverse band the constriction tightens and holds
fast, while a wave of contraction sweeps over the antrum. Another
similar constriction follows. In the interval the transverse band
relaxes slightly, but tightens again when the second wave reaches
it. Perhaps a dozen such waves pass; then a firm contraction at the
beginning of the antrum completely divides the gastric cavity into
two parts. This same division of the stomach into two parts at the
transverse band is to be seen when mustard is given. Now, although
the waves are still running over the antrum, the whole preantral part
of the stomach is fully relaxed. A flattening of the diaphragm and a
quick jerk of the abdominal muscles, accompanied by the opening of the
cardia, now force the contents of the fundus into the œsophagus. As
the spasmodic contractions of the abdominal muscles are repeated, the
gastric wall again tightens around the contained food. Antiperistalsis
I have seen only once; then, while the cat was retching, a constriction
started at the pylorus and ran back, over the antrum, completely
obliterating the antral cavity.

It will be recalled that the principal difference between the
movements of the stomach and their effects as described by Beaumont,
and Hofmeister and Schütz on the one hand, and Rossbach, Roux and
Balthazard, and myself on the other hand, is that the former observed
constrictions completely dividing the stomach at the transverse band,
and the antrum then squeezing its contents into the intestines; whereas
the latter have seen the constrictions moving forward as narrowing
rings, but not separating the gastric cavity into two parts.

With the exception of peristalsis in the antrum, the gastric
movements at the beginning of emesis are almost exactly the same as
those Beaumont, and Hofmeister and Schütz, declare to be the normal
contractions of the stomach. Their observations were made, however,
when the organ was subjected to unnatural stimulation. In the excised
stomach, observed by Hofmeister and Schütz, not only were all nervous
connections severed, but likewise all flow of blood to the organ was
entirely stopped, and the cutting off of the blood supply is regarded
as one of the most powerful predisposing causes of peristaltic action.
The thermometer-tube used by Beaumont was an irritant to the stomach,
as he himself admits. “If the bulb of the thermometer,” he writes, “be
suffered to be drawn down to the pyloric extremity, and retained there
for a short time, or if the experiments be repeated too frequently, it
causes severe distress and a sensation like cramp, or spasm, which
ceases on withdrawing the tube, but leaves a sense of soreness and
tenderness at the pit of the stomach.” Moritz also noticed that a
rubber sound introduced into the human stomach proved to be a source
of irritation. It seems reasonable to suppose, therefore, that these
observers did not see the normal movements, but the actions resulting
from abnormal irritation.

THE EFFECT OF THE MOVEMENTS OF THE STOMACH ON THE FOOD

In my first observations on the active stomach a bulging of the
stomach-wall was to be seen in front of the passing waves. But as
food did not immediately appear in the intestine, and as, after the
pylorus relaxed, the gastric contents did not diminish rapidly enough
to allow the supposition that all of the food squeezed forward by the
waves was immediately forced through the pylorus, it was assumed that
a part, at least, of the food under pressure was forced back towards
the cardia through the constriction-ring. This inference was stated in
the preliminary notice of my work. Roux and Balthazard also observed
the passage of the undulations over the pyloric part, but state merely
that the function of the constrictions is the propulsion of food into
the intestine, without mentioning what must be regarded as a very
important function; namely, the mixing effect of the waves.

Most writers have agreed that the result of the active and passive
movements of the stomach is to force the contents hither and thither,
thus mixing them and the gastric juice together. Two observers,
Beaumont and Brinton, have attempted to explain the manner of the
mixing. Beaumont, after noting how the thermometer-tube, used by him to
indicate the gastric motions, was affected, describes the circulation
of the food as follows: “The bolus as it enters the cardia turns to the
left, passes the aperture, descends into the splenic extremity, and
follows the great curvature towards the pyloric end. It then returns,
in the course of the small curvature, makes its appearance again at
the aperture, in its descent into the great curvature, to perform
similar revolutions.” Brinton bases his theory of the circulation of
the food on an analogy between the movement of a constriction over the
stomach and the passage of a septum with a central perforation along
the interior of a cylinder full of liquid. The result in both cases,
he declares, must be a peripheral current of advance, and a central
current of return. Thus in the stomach there would be peripheral
currents from the cardia along the walls of the stomach to the
pylorus, where they would unite and run as an axial current back to the
cardia.

Certain _a priori_ objections may be urged against each of these
conclusions. In the first place Beaumont’s observations were made on
a subject having a gastric fistula, and the adhesions between the
stomach and the abdominal wall would prevent the fundus from acting
quite normally in relation to its contents. Beaumont’s conclusions,
furthermore, are based on the movements of a thermometer-tube
introduced through the fistula, and on the recognition of particles of
food which he had seen before as they passed the fistulous opening: the
first method, as has been shown, made the conditions in the stomach
more abnormal than they were previously; the second gave uncertain
knowledge of the course of the food when out of the observer’s sight.
Brinton’s hypothesis states the probable movements of fluid contents
acted on by a passing constriction. But it may be objected that the
conditions assumed by him do not exist in all parts of the stomach.
For not only is there no peristalsis visible in the fundus, but with
the usual food the fundus contents are not liquid. Moreover, the
constrictions at the beginning of the pyloric portion are very slight
and move slowly. The food in front of them is, accordingly, not under
much greater pressure than the food behind them. The axial current
which might result, therefore, could not be strong enough to go far
into the cardiac portion.

It is easily possible to test experimentally the validity of these
two theories by watching the action of pieces of food which throw a
black shadow in a dimly outlined stomach. For this purpose little
paste pellets of bismuth subnitrate, with starch enough to keep the
form, were given with the customary meal. These pellets, it was found,
did not break up in the stomach during the gastric digestion of soft
bread. Several times I have been fortunate in getting two of the little
balls in the axis of the stomach and about a centimetre apart. As the
constriction-wave approached them, both moved forward, but not so
rapidly as the wave. Now when the constriction overtook the first ball,
the ball moved backward through the constricted ring, in the direction
of least resistance. The wave then overtook the second ball, and it
also passed backward to join its fellow. At the approach of the next
wave they were both pushed forward once more, only to be again forced
backward, one at a time, through the narrow orifice. As the waves
recurred in their persistent rhythm, the balls were seen to be making
progress--an oscillating progress--towards the pylorus; for they went
forward each time a little farther than they retreated. This to-and-fro
movement of the pellets was much more marked in the antrum, where the
waves were deep, than in the middle region. On different occasions from
nine to twelve minutes have elapsed while the balls were passing from
where the waves first affected them to the pylorus; which means that
on the way they were moved back and forth by more than a half hundred
constrictions.

If the pylorus does not relax, it is evident that a wave approaching it
pushes the food into a blind, elastic pouch, the only exit from which
is through the advancing constricted ring. The constrictions are deeper
near the end of the antrum, and the rings are small; consequently,
the food is squirted back through them with considerable violence. As
has been noted, the pylorus opens less frequently for a while after a
solid piece of food comes to it. In such a case the slow driving waves
squeeze the hard morsel and the soft food about it up to the sphincter,
only to have the whole mass shoot back, sometimes half-way along the
antrum. Over and over again the process is repeated till the sphincter
at last opens and allows the more fluid parts to pass. Hofmeister and
Schütz, and Moritz have disclaimed any selective action of the pylorus,
and declare that solids are driven from the pylorus to the fundus by
antiperistalsis. The action of the pylorus which I have seen, however,
is more like that described by the earlier investigators; for during
digestion there was no antiperistalsis, and the sphincter, separating
the fluids from the solids, caused the solids to remain and undergo a
tireless rubbing. Frequently, when several of these balls have been
given at the same time, they have all been seen in the antrum after the
stomach was otherwise empty. Here they remain to be softened in time
by the juices, or to be forced through the pylorus later, for solids
do pass into the intestine. Thus when the teeth neglect their work the
stomach attempts to perform their function; the relative inefficiency
of the gastric method of grinding and its interference with the normal
gastric activities point an obvious hygienic moral.

During the process of digestion the food in the cardiac portion gives
no sign of currents. Balls which lie in the fundus immediately after
the food is ingested keep their relative positions until the cardiac
portion begins to contract, and then move very slowly towards the
antrum. Moreover, the food in the fundus of a cat has the same mushy
appearance when examined after gastric peristalsis had been active
for an hour and a half that it had when ingested. The contents of
the antrum, on the other hand, look quite different and have the
consistency of thick soup. The inactivity of the food in the fundus
can also be proved by feeding first five grams of bread and bismuth,
then five grams without bismuth, and finally five grams again with
bismuth in it. The stomach contents are thus arranged in two dark
layers along the curvatures, with a light layer between. Tracings made
on tissue paper show that ten minutes after peristalsis commenced the
stratification had entirely disappeared in the pyloric part, but that
an hour and twenty minutes thereafter the layers were still clearly
visible in the cardiac region.

The value of the circulation of the food, as described by Beaumont
and Brinton, lay in the supposition that the contents of the stomach
were thus brought near to the secreting gastric wall, and that the
gastric juice could thus more readily exert its action. Although my
observations do not support their theories of mixing currents running
throughout the stomach, they still show that the pyloric portion is
an admirable device for bringing all of the food under the influence
of the glandular secretions of that region. For, when a constriction
occurs, the secreting surface enclosed by the ring is brought close
around the food lying within the ring in the axis of the stomach.
As this constriction passes on, fresh areas of glandular tissue are
continuously pressed in around the narrow orifice. And also, as
the constriction passes on, a thin stream of gastric contents is
continuously forced back through the orifice, and thus past the mouths
of the glands. The result of this ingenious mechanism is that every
part of the secreting surface of the pyloric portion is brought near to
every bit of food, before the latter leaves the stomach, a half hundred
times or more, as evidence by the moving ball.

SALIVARY DIGESTION IN THE STOMACH

The absence of movement in the fundus would seem to give the food
during its stay there little opportunity to become mixed with the
gastric juices, and thus to undergo peptic digestion. The truth of
this supposition can easily be proved experimentally by feeding a
slightly alkaline meal, and later testing the chemical reaction of the
contents of various parts of the stomach. A cat which had been without
food for fifteen hours was given eighteen grams of mushy bread made
slightly alkaline with sodium carbonate. One hour and a half after
the cat had finished eating she was killed, and the stomach laid bare
by opening the abdomen. A very small hole was then made through the
wall in the fundus region, and another similar hole was made into
the antrum. By means of a glass pipette food was extracted first
from the periphery of the fundus; this food was slightly acid. The
cleaned pipette was then introduced two and a half centimetres into
the fundus contents, and the food thus extracted gave the original
alkaline reaction. Specimens of the liquid contents of the antral and
middle regions, taken from various depths, were all strongly acid.
A dog killed an hour and three-quarters after eating showed similar
differences between the reactions of the food in the fundus and the
food in the pyloric portion. So, as a matter of fact, the food does not
become acid at a uniform rate in all parts of the stomach, as would
be the case if Beaumont’s and Brinton’s theories of mixing currents
were true. Moreover, if the facts accorded with their notions, the
saliva, which ceases to act in the presence of more than 0.003 per
cent free hydrochloric acid, and is destroyed when the percentage
of acid proteids is large, would manifestly have its service as a
ferment limited to the relatively short time during which the stomach
contents, in the process of thorough mixing, were reaching that degree
of acidity. There is, however, no movement of food in the fundus, and
the alkaline food received from the œsophagus remains alkaline in this
region for a considerable period. The nutriment, therefore, if well
chewed and thus mixed with saliva, can undergo salivary digestion in
the fundus for a considerable period without interference by the acid
gastric juice.[32]

From all these observations the conclusion must be that the fundus
acts as a reservoir for the food, in which the digestion of sugars and
starches may take place; and that the pyloric portion with its simple
but marvellous peristaltic mechanism, by a single process, triturates
the food, brings it near to the active glands, stirs it thoroughly with
their secretions, and expels the products into the intestines.

THE INHIBITION OF STOMACH MOVEMENTS DURING EMOTION

Early in the research a marked unlikeness was noticed in the action
of the stomachs of male and female cats. The peristalsis seen with
only a few exceptions in female cats failed to appear in most of the
males, although both had received exactly the same treatment. Along
with this difference was a very striking difference in behaviour when
bound to the holder; the females would lie quiet, mewing occasionally,
but purring as soon as they were gently stroked. The males, on the
contrary, would fly into a violent rage, struggle to be loose from
their fastenings, bite at everything near their heads, cry loudly, and
resist all attempts to quiet them. On account of this difference only
female cats were used for some time, and the significance at first
attributed to the action of the males was almost forgotten when the
following incident recalled it and suggested that the excitement caused
the suspension of the stomach movements. On October 23, 1897, a male
cat was fed at 12.00, but was not placed on the holder till ninety
minutes later. The waves were passing at the rate of six a minute. The
cat fell into a rage and the waves suddenly stopped.

A few days later an observation on a female with kittens explained
the absence of gastric movements in the males. While the peristaltic
undulations were coursing regularly over the cat’s stomach, she
suddenly changed from her peaceful sleepiness, began to breathe
quickly, and struggled to get loose. As soon as the change took place,
the movements in the stomach entirely disappeared; the pyloric portion
relaxed and presented a smooth, rounded outline. I continued observing,
and stroked the cat reassuringly. In a moment she became quiet and
began to purr. As soon as this happened the movements commenced again
in the stomach; first a few constrictions were visible near the end of
the antrum, then a few near the sharp bend in the lesser curvature,
and finally the waves were running normally from their habitual
starting-place. By holding the cat’s mouth closed between the thumb and
last three fingers, and covering her nostrils with the index finger,
she could be kept from breathing. At the first sign of discomfort
the fingers were removed. This experiment was repeated a great many
times on different cats, and invariably the evidence of distress was
accompanied by a total suspension of the motor activities of the
stomach and a relaxation of the antral fibres.

No amount of kneading or compression of the abdomen with the fingers,
short of making the cat angry, would cause the waves to stop; so
that the cat’s movements, in themselves, were not the source of the
inhibition. And since expressions of strong feeling on the part of the
animal always accompanied cessation of the constriction-waves, the
inhibition was probably due to nervous influence. It has long been
common knowledge that violent emotions interfere with the digestive
process, but that the gastric motor activities should manifest such
extreme sensitiveness to nervous conditions is surprising.

SUMMARY

1. By mixing a harmless powder, subnitrate of bismuth, with the food,
the movements of the stomach can be seen by means of the Röntgen rays.

2. The stomach consists of two physiologically distinct parts: the
pyloric part and the fundus. Over the pyloric part, while food is
present, constriction-waves are seen continually coursing towards the
pylorus; the fundus is an active reservoir for the food and squeezes
out its contents gradually into the pyloric part.

3. The stomach is emptied by the formation, between the fundus and the
antrum, of a tube along which constrictions pass. The contents of the
fundus are pressed into the tube and the tube and antrum slowly cleared
of food by the waves of constriction.

4. The food in the pyloric portion is first pushed forward by the
running wave, and then by pressure of the stomach-wall is returned
through the ring of constriction; thus the food is thoroughly mixed
with gastric juice, and is forced by an oscillating progress to the
pylorus.

5. The food in the fundus is not moved by peristalsis, and consequently
it is not mixed with the gastric juice; salivary digestion can
therefore be carried on in this region for a considerable period
without being stopped by the acid gastric juice.

6. The pylorus does not open at the approach of every wave, but only at
irregular intervals. The arrival of a hard morsel causes the sphincter
to open less frequently than normally, thus materially interfering with
the passage of the already liquefied food.

7. Solid food remains in the antrum to be rubbed by the constrictions
until triturated, or to be softened by the gastric juice, or later it
may be forced into the intestine in the solid state.

8. The constriction-waves have, therefore, three functions: the mixing,
trituration, and expulsion of the food.

9. At the beginning of vomiting, the gastric cavity is separated into
two parts by a constriction at the entrance to the antrum; the cardiac
portion is relaxed, and the spasmodic contractions of the abdominal
muscles force the food through the opened cardia into the œsophagus.

10. The stomach movements are inhibited whenever the cat shows signs of
anxiety, rage, or distress.

THE MOVEMENTS OF THE INTESTINES STUDIED BY MEANS OF THE RÖNTGEN
RAYS[33]

BY W. B. CANNON

_From the Laboratory of Physiology in the Harvard Medical School_

Extracts from _American Journal of Physiology_, 1902

INTRODUCTION

The investigation of intestinal movements has been beset by the same
difficulties that characterised the investigation of the gastric
mechanism. Pathological subjects or animals subjected to the disturbing
action of drugs and anæsthetics and of serious operations have been the
only sources of our knowledge. A considerable difference of opinion as
to the nature of the normal movements in the intestines has resulted
from observations made under these necessary abnormal conditions. The
slowly advancing peristaltic wave and the _Pendelbewegung_, or swaying
movement, described by Ludwig, have been regarded as true physiological
processes. Concerning antiperistalsis and the swiftly running
vermicular contraction, observers are not so nearly in agreement.
The activity of the large intestine has been described as simply
peristalsis of a slower rate than that seen in the small intestine.

The best known of the intestinal movements is the normal peristaltic
wave. This wave is slow, having a rate of about two centimetres per
minute, is regular, and by most observers is said to move always in one
direction. The progress of the contraction, as suggested by Nothnagel’s
experiments, and as clearly stated by Mall and by Bayliss and Starling,
is dependent upon a local reflex. According to Mall, when an object
stimulates the mucosa there occurs above the point of stimulation a
constriction which forces the object downward; and as it moves downward
new regions immediately above the mass are by this reflex brought into
constriction, and thus the wave and its stimulus advance together. “At
the same time,” Mall states, “a sucking force, due to active dilatation
below the body, may have a tendency to drag it down.” In what manner
an active dilatation of the intestinal wall may occur so as to produce
a “sucking force” he does not make wholly clear. Bayliss and Starling,
in describing normal peristalsis in the intestine, state that the
contractions above the bolus increase until there is a strong tonic
constriction. This passes the bolus onward, and as it advances the ring
of constriction follows it. While the bolus is passing down, the gut
above it is traversed by waves running as far as the constricted ring.
These observers state the law of intestinal peristalsis thus: “Local
stimulation of the gut produces excitation above and inhibition below
the excited spot.”

The pendulum movements are characterised by a gentle swaying motion
of the coils, and are accompanied by rhythmical contractions of the
intestinal wall. They continue with undiminished force after paralysis
of the local nervous mechanism by nicotine or cocaine; they have been
called, therefore, myogenic or myodromic contractions. Observers have
described them variously as shortenings and narrowings of the gut,
rhythmically repeated at nearly the same intestinal circumference; as
alternating to-and-fro movements of the long axis without changes in
the lumen; as local or extensive periodic contractions and relaxations
mainly of the circular musculature; and as waves involving both
muscular coats of the intestine, and travelling normally from above
downward at a rapid rate (2 to 5 cm. per second). They have been
seen in the dog, and in the rabbit and cat. In the cat Bayliss and
Starling noticed that when the lumen of the gut was distended by a
rubber balloon, there appeared rhythmical contractions, which nearly
always were most marked at about the middle of the balloon; _i. e._,
the region of greatest tension. This form of constriction, which,
as my observation shows, is an indication of the manner in which
the rhythmical contraction acts in the cat’s intestine, Bayliss and
Starling seem to have regarded with slight attention, since it did not
accord with the law of peristalsis.

The swift vermicular wave may pass the whole length of the intestine
in about a minute. It is often seen just after death, as well as in
pathological states such as intestinal anæmia or hyperæmia, and when
the bowel contains gases and organic acids from decomposing food.
Starling is inclined to regard this type of intestinal activity as an
exaggeration of the rhythmic type; Mall, on the other hand, places
it in a class by itself, and declares that its service is to rid the
intestine rapidly of irritating substances. Nothnagel, who designates
this form of movement with the term _Rollbewegung_, thinks it is
transitional between a physiological and a pathological activity.

The existence of antiperistalsis has been so much questioned that
it will be considered in a special section of this paper, where my
observations may be conveniently introduced.

The common understanding of the manner in which food passes through the
intestinal canal is that the chyme ejected from the stomach is pressed
downward by a peristalsis, which passes slowly over a part or all of
the small intestine. The peristaltic waves of the colon are supposed
to constitute an independent group, similar to those of the small
intestine, but weaker and slower. Movements of the food other than the
uninterrupted advance have been mentioned by some observers. Starling
states that the effect of the pendulum movement is to mix the contents
of the intestine and bring them into intimate contact with the mucous
membrane. Grützner writes that he has been brought “by strange and
peculiar observations” to believe that the fluid contents of the small
intestine move irregularly forward, then forward and back, then perhaps
remain quiet for some time, only to pass backward for a long distance,
and finally to move forward steadily to the end. In this manner the
food is mixed and brought into contact with the absorbing walls. The
to-and-fro shiftings of the food Grützner ascribed to advancing and
retrograde contractions of the intestinal musculature, and he argued
that even circular constrictions must force the liquid contents away
in both directions. To support his contention, Grützner introduced
mercury into the intestine and observed it with the Röntgen rays. After
noting a backward and forward movement of the mercury he dismissed the
method, saying, “Many a flash must come from the Röntgen tube before
the _normal_ movement of the intestinal contents is made entirely clear
by this method.”

The following account is a summary of many repeated observations on
different animals, and is a contribution to a clear understanding of
the normal movements of the intestines and their contents.

THE MOVEMENTS OF THE SMALL INTESTINE

When the food has been distributed through the intestine so as to
present the appearance shown in Figure 1, a noticeable feature in most
or all of the loops is the total absence of movement. If the animal
remains quiet, however, only a few moments elapse before peculiar
motions appear in one or another of the loops, or perhaps in several,
and last for some time. These motions consist in a sudden division
of one of the long, narrow masses of food into many little segments
of nearly equal size; then these segments are again suddenly divided
and the neighbouring halves unite to make new segments, and so on, in
a manner to be more fully described. I have called this process the
rhythmic segmentation of the intestinal contents. Further observation
reveals peristalsis here and there, and under certain circumstances the
typical swaying movements may be seen. All these phenomena are now to
be considered in detail.

[Illustration:
FIGURE 1.--Appearance of food in the intestines 5¾ hours after eating.
This and other radiographs reduced two-thirds.]

[Illustration:
FIGURE 2.--Diagram representing the process of rhythmic segmentation.
Lines 1, 2, 3, 4 indicate the sequence of appearances in the loop.
The dotted lines mark the regions of division. The arrows show the
relation of the particles to the segments they subsequently form.]

_Rhythmic segmentation of the intestinal contents._--This is by far the
most common and the most interesting mechanical process to be seen in
the small intestine. The nature of the process may best be understood
by referring to the diagram in Figure 2. A string-like mass of food
is seen lying quietly in one of the intestinal loops (line 1, Fig.
2). Suddenly an undefined activity appears in the mass, and a moment
later constrictions at regular intervals along its length cut it into
little ovoid pieces. The solid string is thus quickly transformed,
by a simultaneous sectioning, into a series of uniform segments. A
moment later each of these segments is divided into two particles,
and immediately after the division neighbouring particles (as _a_
and _b_, line 2, Fig. 2) rush together, often with the rapidity of
flying shuttles, and merge to form new segments (as _c_, line 3, Fig.
2). The next moment these new segments are divided, and neighbouring
particles unite to make a third series, and so on. At the time of the
second segmentation (line 3, Fig. 2) the end particles are left small.
Observation shows that these small pieces are not redivided. The end
piece at A simply varies in size with each division; at one moment it
is left small, at the next moment it is full size from the addition
of a part of the nearest segment, and a moment later is the small bit
left after another division. The end piece at B (probably the rear
of the mass) shoots away when the end mass is divided, and is swept
back at each reunion to make the large end mass again, only to be
shot away and swept onward with each recurrence of the constrictions.
Thus the process of repeated segmentation continues, with the little
particles flitting towards each other and the larger segments shifting
to and fro, commonly for more than half an hour without cessation.
From the beginning to the end of a period of segmentation the food
is seen to have changed its position in the abdomen to only a slight
extent; whether this change is a passing of the food along the loop,
or a movement of the loop itself, it is impossible to tell from the
shadows on the screen. The change of position, however, is much less
conspicuous than the lively division and redivision which the mass
suffers so many times from the busy, shifting constrictions.

From this typical form of rhythmic segmentation there are several
variations. Sometimes, and especially when the mass of food is thick,
the constrictions do not make complete divisions and are so far apart
that the intermediate portions are relatively large. Moreover, the
constrictions do not take place in the middle of each portion, but
near one end; thus each portion is constricted, not into halves,
but into thirds. If a little pointer is placed at the middle of a
segment, when the segments are completely divided into halves, in a few
seconds the pointer will be in the middle of the clear space between
two segments; but in a few seconds more the first phase will return
and the pointer will again be indicating a segment,--two operations
intervene between similar phases. When, however, the portions are
constricted into thirds, the indicator shows it, since three operations
intervene between similar phases. The manner of these changes is made
clearer by reference to the diagram in Figure 3. That each portion is
constricted into three pieces is proved also by watching the gradual
reduction of the portion at the left end of line 1 through lines 2
and 3, and also in the gradual formation of a full-sized portion at
the right end of lines 2, 3, and 4. When food undergoing this process
is watched, it appears to be affected by a series of constrictions,
each of which starts at one end of the mass and marches through to the
other end, leaving its impress at short intervals along the length. The
progression of the dotted lines from right to left in _a_, _b_, _c_,
and _d_, etc., Fig. 3, gives a notion of these advancing constrictions.

Another variation of the segmentation is shown in Figure 4. In this
type there are evidently divisions and subdivisions, _i.e._, one more
operation between the appearance and the reappearance of the same phase
than is present in the simple division of the small segments in a long
string of food (Fig. 2). This form of segmentation is fairly typical
for the constrictions seen in food advancing through the intestine.
Sometimes the divisions occur in the middle of a long string of food
and leave the ends wholly unaffected.

[Illustration:
FIGURE 3.--Diagram showing the relations of the portions when they are
constricted into three pieces. The dotted lines indicate regions of
constriction; the arrows indicate the relationship of the pieces to
the portions they subsequently form.]

A remarkable feature in the segmentation of the food is the rapidity
with which the changes take place. The simplest way of estimating the
rate of division is to count, not the number of times the partition of
the food recurs in the same place, but the number of different sets of
segments observed in a given period. Thus in Figure 4 the appearances
of lines 1, 2, 3, 4, etc., would be counted, and not merely lines 1,
4, etc. Repeated observations on different animals have shown that
the most common rate of division in long, thin chains of food varies
between twenty-eight and thirty times in a minute; _i. e._, there is
a change from one set of segments to another set every two seconds,
and a return of the same phase every four seconds. In some cases the
rate is as low as twenty-three times per minute. The larger masses seem
to be associated with a slower segmentation; the operations indicated
in Figure 3, for example, occurred from eighteen to twenty-one times
in a minute, so that the same phase reappeared only once in eight or
nine seconds. The segmentation frequently continues for more than half
an hour; in one instance it was seen to persist with only three short
periods of inactivity for two hours and twenty-two minutes. At the rate
of thirty segmentations per minute it is clear that a slender string
of food may commonly undergo division into small particles more than a
thousand times while scarcely changing its position in the intestine.

I have seen once, in a cat only lightly etherised, the exterior of an
intestine which was dividing the food as above described. An hour and
a half after a meal of salmon the anæsthetic was given, the abdomen
opened, and the flaps raised so as to form walls. Warm salt solution
was then poured into the abdominal cavity, and the floating coils left
covered with the transparent omentum. The gastric peristaltic waves
were running regularly; on the intestine there were visible at various
places during the period of observation regions of constriction which
had the appearance shown in Figure 3, except that the rings were
relatively nearer together. New rings of constriction took place on the
same side of all the bulging parts at the margin of the constricted
portion (_cf._ dotted lines, Fig. 3). As new rings occurred the old
relaxed, but apparently with tardiness, for the contents gurgled as
if forced through the narrowed lumen. The constrictions recurred
irregularly and at much longer intervals than in the normal animal. The
contracted rings were pale and bloodless.

The effect of the process of rhythmic segmentation proves it an
admirable mechanism. The food over and over again is brought into
closest contact with the intestinal walls by the swift kneading
movement of the muscles. Thereby not only is the undigested food
intimately mixed with the digestive juices, but the digested food is
thoroughly exposed to the organs of absorption. Mall has shown that
contraction of the intestinal wall has the effect of pumping the blood
from the submucous venous plexus into the radicles of the superior
mesenteric vein, and thus materially aids the intestinal circulation.
Moreover, lacteals loaded with fat will in a few moments become empty
unless the intestine is slit lengthwise, so that the muscles cannot
exert compression. The rhythmic constrictions, therefore, both
propel the blood in the portal circulation and act like a heart in
promoting the flow of lymph in the lacteals. This single movement with
its several results is an excellent example of bodily economy; the
repeated constrictions, as already shown, thoroughly churn the food and
digestive fluids together, and also plunge the absorbing mucosa into
the very midst of the food masses: but not only are the processes of
digestion and absorption favoured by these movements; they also, by
compression of the veins and lacteals of the intestinal wall, serve
to deport through blood and lymph channels the digested and absorbed
material.

_Peristalsis._[34]--The phenomena of peristalsis and segmentation are
usually combined in some manner while the food passes through the small
intestine. Peristalsis is observed normally in two forms: as a slow
advancing of the food for a short distance in a coil, and as a rapid
movement sweeping the food without pause through several turns of the
gut. The latter form is frequently seen when the food is carried on
from the duodenum; and it may readily be produced in other parts of the
small intestine by giving an enema of soapsuds.

When a mass of food has been subjected for some time to the segmenting
activity of the intestine, the separate segments, instead of being
again divided, may suddenly begin to move slowly along the loop in
which they lie. That this movement is not a swinging of the coil as
a whole, but a peristaltic advance of separate rings of its circular
musculature, is made probable by the fact that the succeeding segments
follow along the same path their predecessors have taken. The advance
of the little pieces may continue for seven or eight centimetres,
when finally the front piece stops or meets other food. Then all the
succeeding pieces are swept one by one into the accumulating mass,
which at last lies stretched along the intestine, a solid string
manifesting no sign of commotion.

[Illustration:
FIGURE 4.--Diagram showing combined peristalsis and segmentation.]

Another form of slow peristalsis is frequently observed when the food
is pushed forward, not in small divisions, but as a large lump. The
relatively long string of food is first crowded into an ovoid form as
the forward movement begins, and as it is collecting thus, it seems
at the last to be suddenly formed into a more rounded ball, as if the
mass were pulled or pushed together at the two ends. The next moment
it is indented in the middle by a circular constriction (as shown in
Fig. 4, line 2), which spreads it in both directions along the loop.
The trailing portion (_a_) is next cut in two, and the severed part
sometimes flies back over its course about a centimetre. Now the whole
mass is swept together again and slightly forward as shown in line 4,
Fig. 4, and the segmenting process is repeated. At stage 3, Fig. 4,
a constriction sometimes appears around the middle of the advanced
portion (_b_). Thus, with many halts and interruptions, the food slowly
advances.

A slight variation of the movement just described is observed when the
amount of food is greater and extends farther along the intestine.
Under such circumstances, as the mass moves forward, constrictions
appear just in front of the rear end, which separate it from the main
body, and cause it to shoot backward sometimes through the distance of
a centimetre. The main body meanwhile is not disturbed. No sooner has
the rear section been shot away than it is swept forward again into
union with the rest of the food, and the whole mass then advances until
another interfering constriction repeats the process.

_Rhythmic segmentation and the pendulum movement._--There is little
doubt that the segmentation of the food which I have seen is due
to an activity of the intestinal musculature similar to that which
causes the so-called pendulum movement. This activity, as already
noted, is rhythmic, and, although accounts differ, analytical methods
prove that it involves both the longitudinal and the circular layers
of muscle. Observations of the effect of the rhythmic contractions
upon the food show that the action of the circular fibres is most
prominent. It is probable, however, that the longitudinal fibres also
play an important part in the process of segmentation. Examination
of Figure 2 makes clear that in line 2 the regions of constriction
appear between the regions of constriction in line 3; before _c_ can
be formed, therefore, the constriction between _a_ and _b_ must relax.
Contraction of the longitudinal fibres between two segments would help
to enlarge the constricted lumen of the gut. It seems probable that, as
the constrictions on either side of _c_ occur, the longitudinal fibres
between them contract; almost simultaneously the constriction between
_a_ and _b_ relaxes, and the two particles are thus brought swiftly
together. A similar process naturally would take place for each of
the shifting segments. Thus the function of the longitudinal muscles
would be to contract between new rings of constriction and thereby aid
in relaxing the former ring between them. During my one observation
of the segmenting process, as seen on the surface of the intestine,
I could not be sure that the distance between neighbouring segments
was shortened as the constriction relaxed; that activity of the
longitudinal fibres is present, however, is indicated by observations
of Raiser on the intestines of the rabbit and the cat. Raiser observed
the outer surface of the coils, and describes the normal movement
as an alternate contraction and relaxation of single divisions of
the longitudinal fibres; he notes that these short divisions shift.
But whether they shift in alternation with the shifting circular
constrictions, as seems probable, is an interesting point not yet
determined.

[Illustration: FIGURE 5.--Tracing showing segmentation of chyme in the
duodenum. This and other tracings reduced two-thirds.]

Bayliss and Starling state that the swaying pendulum movements are
essentially due to peristaltic waves recurring in the same place and
running rapidly downward. This form of the movements I have seen only
once. At this time about 90 c.c. of soapy water had been injected.
This procedure has the effect of exaggerating in every particular the
movements of the small intestine. In this instance a broad constriction
appeared about the middle of a long string of food and persisted there
while it spread down the gut. As the contraction spread, the gut swayed
slowly to and fro before it. Then there was a relaxation, followed by
a recurrence of the constriction in the same place, a spreading of the
contraction, and a swinging of the loop just as before. This phenomenon
was repeated again and again, till finally the string was divided and
the forward piece pushed through a tortuous course to the colon.

_The course of the food in the small intestine._--Chyme is not forced
from the stomach by every wave that passes over the antrum, but only
at intervals. When the pylorus relaxes, the food, moved towards the
pylorus under considerable pressure, is squirted along the duodenum
for two centimetres or more. Careful watching of this food shows that
usually it lies for some time in the curve of the duodenum until
additions have been made to it from the stomach, and a long, thin
string of food is formed. While it is resting in this place it is
exposed to the outpouring of the bile and pancreatic juices. All at
once the string becomes segmented (see Fig. 5) and the process of
rhythmic segmentation continues several minutes, thoroughly mixing
the intestinal digestive juices with the chyme. In this region the
alternate positions of the segments are sometimes far apart, and the
to-and-fro movements of the particles may be a relatively extensive
and very energetic swinging. Finally the little segments unite into
a single mass, or form in groups, and begin to move forward. The
peristalsis here, as already mentioned, is much more rapid than the
normal peristalsis elsewhere in the small intestine. The masses, once
started, go flying along, turning curves, whisking hither and thither
in the loops, moving swiftly and continuously forward. After passing on
in this rapid manner for some distance the food is collected in thicker
and longer strings, resembling the strings seen characteristically in
the other loops. Towards the end of digestion the small masses shot
out from the stomach, after a few segmentations, may move on in the
rapid course without being accumulated in a larger mass until the swift
movement ceases.

During the first stages of digestion in the cat’s small intestine the
food usually lies chiefly on the right side of the abdomen; during the
last stages the loops on the left side contain the greater amount of
food. In these loops the food remains sometimes for an hour or more
with no sign of movement. All at once a mass begins to show irregular
depressions and elevations along its length, and then suddenly it is
divided, at first partially, later completely, into many little equal
parts, and these repeatedly undergo division and reunion, division
and reunion, over and over again, in the manner described above as
rhythmic segmentation. After a varying length of time the activity
wanes and the little segments are carried forward individually and
later brought together, or join and move on as a single body, or they
may reunite and lie quietly for some time without further change. Thus
by a combined process of kneading and peristaltic advance the food is
brought to the ileocæcal valve to enter the large intestine. Records
from ten different animals show that salmon does not appear in the
small intestine until an hour or an hour and a half after the food is
eaten. Inasmuch as five or six hours elapse after eating before this
food begins to be seen in the colon, it is evident that the chyme takes
four to five hours to pass the length of the small intestine. It is
interesting to note that the operations are considerably shortened if
the meal has consisted of bread and milk.

THE COMPETENCE OF THE ILEOCÆCAL VALVE

The ileocæcal valve in the cat is situated three or four centimetres
from the blind end of the cæcum. Its position is usually marked in
shadows of the food in the colon by a slight indentation, towards which
masses about to enter the colon are ordinarily directed from a point
somewhat distant in the small intestine (see Fig. 6).

Regarding the competence of the ileocæcal valve many observations
have been made. Grützner has reviewed the evidence bearing on the
question and concludes that the valve is not competent, least of all
for liquids. He declares that as soon as liquids or thin fluid masses
appear in the upper part of the colon they pass in many instances into
the small intestine the moment that the pressure on the colon side
rises slightly. If the colon contains a solid or a thick, mushy mass,
the passage towards the small intestine is scarcely possible, because
every increase of pressure in the large intestine must force the two
lips of the valve together and close it.

The importance of the competence of the ileocæcal valve under normal
conditions cannot be appreciated until the function of the first part
of the colon is considered. In order that this part of the intestinal
mechanism may perform its service, the competence of the valve for the
food which enters the colon from the ileum should be perfect. As a
matter of fact, such is the case. Not only does the activity of the
colon prove this statement, but the failure of every attempt to drive
the food in the colon back through the valve into the ileum confirms
the proof. Again and again I have tried, by manipulation through the
abdominal wall, to press the normal contents of the colon downward with
sufficient force to cause them to return to the small intestine, but
without success. The valve held perfectly.

THE MOVEMENTS OF THE LARGE INTESTINE

When the large intestine is full, palpation through the abdominal wall
demonstrates that the material in the lower descending colon and in
the sigmoid flexure is usually composed of hard, incompressible lumps,
while that in the ascending and transverse colon and the cæcum is
soft, permitting the walls of the gut to be easily pushed together.
The condition of the contents in these two regions seems to indicate
a rough division of the large intestine into two parts, and the
mechanical activities of these two parts verify the differentiation. In
the descending colon the material is very slowly advanced by rings of
tonic constrictions (see Fig. 7); in the ascending and transverse colon
and in the cæcum by far the most common movement is an antiperistalsis.

_Antiperistalsis in the colon._--The colon of cats which have been
without food for a day usually contains enough gas to make the position
of the gut distinguishable with the fluorescent screen (see Fig. 1).
The first food to enter the colon from the small intestine is carried
by antiperistaltic waves into the cæcum (Fig. 1), and all new food as
it enters is also affected by these waves. Thus the contents of the
colon, instead of being driven immediately toward the rectum by slow
peristalsis, as is the general opinion, are first repeatedly pushed
toward the cæcum by an antiperistaltic action.

These antiperistaltic waves follow one after another like the
peristaltic waves of the stomach (see Figs. 5, 6, and 10). They begin
either on the more advanced portion of the food in the colon (when only
a small amount is present), or at the nearest tonic constriction, which
is usually at the turn between the transverse and descending colon
(Figs. 7 and 8.) The waves rarely run continuously for a long time.
When the colon is full, it is usually quiet. The first sign of activity
is an irregular undulation of the walls, then very faint constrictions
passing along the gut towards the cæcum. These constrictions may
first appear only on the ascending colon. As they continue coursing
over the intestine they become deeper and deeper, until there is a
marked bulging between successive constrictions. When the waves have
thus become more prominent, they are seen to start near the end of
the transverse colon and pass without interruption to the end of the
cæcum. After these deepest waves have been running for a few minutes
the indentations grow gradually less marked, until at last they are so
faint as to be hardly discernible. The final waves are sometimes to be
observed only at the end of the transverse colon.

Such a period of antiperistalsis lasts from two to eight minutes,
with an average duration of four or five minutes. The periods recur
at varying lengths of time; in one instance a period began at 1.38
P.M. and was repeated at 2.06, 2.34, 2.55, 3.15, and at 3.36, when
the observation ceased; in another instance a period began at 2.43
P.M., and was repeated at 2.57 and at intervals of from ten to fifteen
minutes thereafter while the animal was being watched. The waves have
nearly the same rate of recurrence as those in the stomach; about five
and a half waves pass a given point in a minute, _i. e._, eleven waves
in two minutes. This rate has proved fairly constant in different cats
and at different stages in the process of digestion; in one case,
however, the waves passed at the rate of nine in two minutes.

The stimulating effect of rectal injections on the movements of the
small intestine has already been noted. Enemata have also pronounced
stimulating action on the antiperistalsis of the colon. Usually the
almost immediate result of a rectal injection of warm water is the
appearance of deep antiperistaltic waves, which often continue running
for a long period. In one case, after an injection of 50 c.c. of warm
water, the waves followed one another with monotonous regularity during
an observation lasting an hour and twenty minutes. The manner in which
this antiperistaltic mechanism affects nutrient enemata introduced into
the bowel will be discussed in the section devoted to the question of
antiperistalsis.

These constrictions passing backward over the colon do not force
the normal contents back through the valve into the small intestine
again. I have seen hundreds of such constrictions, and only twice have
there been exceptions to this rule,--once under normal conditions,
when a small mass slipped back into the ileum, and at another time
when a large amount of water had been introduced into the colon. The
importance of the competence of the ileocæcal valve is now apparent;
indeed, antiperistalsis in the colon gives new meaning and value to
the location of a valve at the opening of the ileum. For, inasmuch
as the valve is normally competent, the constrictions repeatedly
coursing towards it force the food before them into a blind sac. The
effect on the food must be the same as the effect seen in the stomach
when the pylorus remains closed before the advancing waves. The food
is pressed forward by the approach of each constriction; but since
it cannot go onward in the blind sac, and is, moreover, subjected to
increasing pressure as the constriction comes nearer, it is forced
into the only way of escape, _i. e._, away from the cæcum through
the advancing constricted ring. About twenty-five waves affect every
particle of food in the colon in this manner during each normal period
of antiperistalsis. The result must be again a thorough mixing of the
contents and a bringing of these contents into close contact with the
absorbing wall--a process which has already been variously repeated
many times in the stomach and in the small intestine.

Two other movements have been observed in the ascending colon, but
they are rare appearances. The first of these was a serial sectioning
of the contents noticed in an animal given castor oil with the food.
A constriction separated a small segment in the cæcum; another
constriction then cut off a segment just above the first, and with the
disappearance of the first constriction the two separated segments
united. A third segmentation took place above the second, and the
changes occurred again. Thus the whole mass was sectioned from one
end to the other; and no sooner was that finished than the process
began again and was repeated several times. A slight modification of
this movement was observed in a colon containing very little food. The
mass was pressed and partially segmented in the manner characteristic
of the small intestine, and was thus again and again spread along
the ascending colon, and each time swept back into a rounded form
by antiperistalsis. The second of the two movements mentioned above
consisted in a gentle kneading of the contents. This was caused by
broad constrictions appearing, relaxing, appearing, relaxing, over
and over again, in the same place. When several of these regions were
active at the same time, they gave the food in the colon the appearance
of a restless undulatory mass. Once a constriction occurred and
remained permanently in one place, while the bulging parts on either
side of it pulsated alternately, at the rate of about eighteen times
in a minute, with the regularity of the heart-beat. Although these
phenomena are somewhat striking, they are not usual, and are in no way
so important as the antiperistalsis.

_The changes when food enters the colon._--The passage of food through
the ileocæcal valve seems to stimulate the colon to activity. As food
is nearing the ileocæcal valve the large intestine is usually quiet and
relaxed (Fig. 6, 4.00), though occasionally indefinite movements are
to be observed; and sometimes just before the food reaches the end of
the ileum the circular fibres of the colon in the region of the valve
contract strongly, so that a deep indentation is present there. The
indentation may persist several minutes; it disappears as the muscles
relax just previous to the entrance of the food. The food is moved
slowly along the ileum and is pushed through the valve into the colon.
The moment it has entered a strong contraction takes place all along
the cæcum and the beginning of the ascending colon, pressing some of
the food onward, and a moment later deep antiperistaltic waves (Fig. 6,
4.03) sweep down from the transverse colon and continue running until
the cæcum is again normally full, _i. e._, for two or three minutes.

[Illustration:
FIGURE 6.--Tracings showing changes when food enters the colon and
also the first tonic constriction. 4.00, the colon relaxed as food
approaches in the ileum. 4.03, the colon contracted and traversed by
antiperistaltic waves after the food has entered.]

_The appearance of tonic constrictions._--It has already been noted
that as the food accumulates in the ascending colon it is at first
confined to this region by antiperistaltic waves. With further
accessions, however, the contents naturally must be pressed more and
more into the transverse and descending colon. In the early stages of
this accumulation, while the food lies chiefly in the ascending colon,
the only activity of the muscular walls is the antiperistalsis. As the
contents extend along the intestine a deep constriction appears near
the advancing end and nearly separates a globular mass from the main
body of the food (Fig. 6). The contents of the large intestine progress
farther and farther from the cæcum; meanwhile new tonic constrictions
appear which separate the contents into a series of globular masses.
And as the number of these divisions increases they take a position
farther from the cæcum, so that they are present chiefly in the
descending colon (Fig. 7). Raiser has recorded a similar appearance
in the terminal portion of the rabbit’s colon, in which deep circular
constrictions separate the scybalous masses. He maintains that these
masses are pushed onward by the constrictions. Comparing tracings
made at rather long intervals (forty-five minutes), I found that the
rings disappear from the transverse colon, and then are present with
the waste material in the descending colon. Thus in the cat also
these rings, which seem with short observation to be remaining in one
position, are in reality moving slowly away from the cæcum, pushing
the hardening contents before them. The contents at this stage are no
longer fluid, and consequently they must offer considerable resistance
to a force pushing them through the colon. It is an advantage to have
this pultaceous substance propelled in divisions rather than in a
uniformly cylindrical mass, since the fibres along the length of the
mass are thereby rendered effective. Such are the functions of the
persistent rings; they form the waste matter into globular masses at
the end of the transverse colon and slowly push these masses onward.

[Illustration:
FIGURE 7.--Radiograph showing the region of tonic constrictions
(descending colon) and the region of antiperistalsis (transverse and
ascending colon).]

In the transverse colon, which is free from the slowly moving rings,
the antiperistaltic waves have full sway. In the region of the
tonic rings an infrequent or even a slowly periodic relaxation and
contraction are often to be observed. These changes seem to take place
in all the rings at about the same time. Once I saw antiperistaltic
waves running over the uppermost of four segments, but since the rings
on either side of the segment held tightly, the waves had merely the
effect of churning the material of the segment and did not move it
onward. Inasmuch as the material in these segments at first is soft, so
that the segments are easily compressible, while the fæcal masses which
are the final result are relatively hard and dry, it follows that even
within the confines of these persistent rings some absorption is taking
place.

DEFECATION

The process of clearing the colon is a process of repeated reduction
of the amount of material present. Figure 8 (3.11) is a radiograph
showing the food in the colon at 3.11 P.M. About 3.25, with a slow,
sweeping movement, the gut swung around so that the ascending colon was
lying in the position of the last half of the transverse colon, and the
transverse colon had taken the position of the descending part (Fig.
8, 3.25). At the same time the tonic constrictions disappeared and
were replaced by a strong, broad contraction of the circular muscle,
tapering the contents off on either side in two cones. The region of
strongest contraction was apparently drawn downward with the rest of
the gut by a shortening of the descending colon. As the intestine
swung around, more material was forced into the rectum, and when the
swinging of the intestine stopped, the constriction which divided
the lumen passed slowly downward, and with the aid of the muscles
surrounding the abdominal cavity, pushed the separated mass out of
the canal.[35] After the terminal mass had thus been pushed out, the
colon with the remainder of its contents returned to nearly its former
position (Fig. 8, 3.46). About two hours afterward this remnant had
been spread throughout the length of the large intestine by means of
the slowly moving rings. Figure 7 is a radiograph of the same colon
pictured in Figure 8; the radiograph was taken at 11.50 A.M., and at
12.15 P.M. the material in the lower descending colon was forced out in
the manner above described. Within three hours the remaining portion
had been spread into the evacuated region, as shown in Figure 8, 3.11.
The manner in which the material is spread from the region of the
antiperistaltic waves into the region of the slowly advancing rings
presents a problem. During normal living new food constantly arriving
in the colon must force the old contents forward just as the later
parts of a meal force forward the earlier parts; there is no doubt,
however, that most of the contents of the cæcum and the ascending colon
may be passed onward even during starvation. The emptying of these
regions, according to my observations, is never complete; for after
considerable time has elapsed and the large intestine is cleared and
dilated with gas, some substance is still to be detected in the cæcum
and clinging to the walls of the ascending colon. The only activities
manifested here are the antiperistaltic waves and the strong tonic
contraction of the whole circular musculature shown in Figure 6. It is
clear that the latter activity would serve to press into the transverse
colon a considerable portion of the contents of the ascending colon,
and the remnant seen clinging to the walls would be the part not thus
pressed forward.

[Illustration:
3.11 3.25 3.46

FIGURE 8.--Two radiographs and a tracing showing the changes taking
place in defecation. 3.11, material in the colon. 3.25, colon carried
downward and terminal mass separated. 3.46, after defecation, when the
colon returns to former position. Defecation occurred at 3.27.]

Twice I have seen appearances which might account for the emptying of
the first portion of the large intestine in a more thorough manner
than that above described. At one time, without apparent stimulation,
strong tonic contraction occurred along the entire length of the
ascending colon, which forced the contents almost wholly into the
transverse portion. This action seemed merely an exaggerated form of
that observable after food passes the ileocæcal valve (see Fig. 6). At
another time, after a mass of food had passed through the ileocæcal
valve, after the ascending colon had contracted generally and the
antiperistaltic waves had coursed over it in the usual manner, a deep
constriction appeared at the valve and ran upward without relaxation
nearly the length of the ascending colon, pushing the contents before
it. For an instant the wave paused; then the constriction relaxed and
the food returned towards the cæcum. These observations indicate that
either a general contraction of the wall of the large intestine or a
true peristalsis may be effective in pressing waste matter from the
region where antiperistalsis is the usual activity into the region
where the slowly advancing rings may carry it on to evacuation (see
Fig. 7).

THE QUESTION OF ANTIPERISTALSIS

In 1894 Grützner published an observation and made an assumption about
which there has since been much controversy. He maintained that when
normal salt solution, holding in suspension hair, powdered charcoal, or
starch grains, is injected into the rectum, it is carried upward into
the small intestine and may even enter the stomach. These experiments
have been repeated by several observers. Some have confirmed Grützner’s
results; others have failed, after using most careful methods, to
find any evidence of the passage of the injected material back to the
stomach, and they have declared that the apparent success was due to
carelessly allowing the food of the animal to become contaminated with
the test materials, so that these were introduced into the stomach by
way of the mouth. That antiperistalsis does not occur in the small
intestine seems to be proved by Mall’s experiment of reversing a
portion, sewing it in place, and then finding that the food does not
pass the reversed region, but collects at the upper end. Sabbatani
and Fasola reversed stretches of small intestine of varying length,
and found that the reversed portions allowed fluids to pass, but that
the persistence of the physiological direction of movement caused an
accumulation of undigested food in the region of the upper suture.
However a portion of the intestine lay in relation to the rest, it
always manifested the normal peristalsis. Many other observers working
directly on the intestine confirm this testimony and state that the
progress of the constriction-rings is always downward, and that
antiperistalsis is not physiological. In 1898, however, Grützner took
his stand again in favour of a backward movement in the intestines,
and in a somewhat metaphysical manner argued that peristalsis and
antiperistalsis belong to each other just as relaxation of muscle is
related to contraction. He assumed that as the contents are advanced
by slow peristalsis, so are they returned by a similar movement in
the opposite direction, and he mentions several pathological cases
(fistula of intestine) to substantiate the assumption.

By means of the X-rays it is possible to see just what takes place when
a fluid is injected into the rectum. For the purpose of determining
how nutrient enemata are received and acted upon in the intestines,
I have introduced thin, fluid masses in large and small amounts, and
thick, mushy masses in large and small amounts, in different animals.
The enemata consisted of 100 c.c. of milk, one egg, ten to fifteen
grams of bismuth subnitrate, and two grams of starch to hold the
bismuth powder in suspension. To make the thick enema all these were
stirred together and boiled to a soft mush; to make the thin enema
all the parts were boiled together except the egg, which was added
after the boiled portion was cooled. The small amount injected was 25
c.c.; the large amount almost 90 c.c., about the capacity of the large
intestine when removed from the body. The animals were given first a
cleansing injection, and after this was effective the nutrient material
was introduced. In order to make sure of the observation, a control
radiograph was first taken to show no bismuth food present, and other
radiographs taken at varying intervals after the injection to record
the course the food was following.

[Illustration:
1.50 2.15 3.00

FIGURE 9.—- Radiographs showing that after a large nutrient enema
(about 90 c.c.) has been given the food is forced more and more from
the large into the small intestine. The enema was introduced at about
1.40 P.M. At 3.00 segmentation was occurring in many loops.]

These experiments show that when small amounts of nutrient fluid are
introduced they lie first in the descending colon. In every instance
antiperistaltic waves are set going by the injection, and the material
is thereby carried to the cæcum. When large amounts are injected they
stop for a moment in the region between the transverse and descending
colon, as if a constriction existed there. Then a considerable amount
of the fluid passes the point, and antiperistaltic waves carry it
to the cæcum. In any case the repeated passing of the waves seems
to have the effect of promoting absorption, for in the region where
these waves continue running, the shadows become gradually more dim,
and finally the bismuth appears to be only on the intestinal walls;
in other regions, _e. g._ in the descending colon, the shadows retain
their original intensity. Small injections have never in my experience
been forced even in part into the small intestine; but with the larger
amounts, whether fluid or mushy, the radiographs show many coils of the
small intestine containing the bismuth food.

The passage of the injected material beyond the ileocæcal valve is
probably due entirely to antiperistalsis in the colon,--a factor
unknown to both Grützner and his opponents. The valve, which is
thoroughly competent for food coming normally from the small intestine
into the large, is curiously incompetent for a substance, even of the
consistency of thick cream, introduced in large amount by rectum. When
the valve first permits the food to enter the ileum, the fluid pours
through and appears suddenly as a winding mass occupying several loops
of the intestine (Fig. 9, 1.50, about ten minutes after the injection).
The mass is continuous from the valve to the other end; antiperistalsis
is therefore not visible in the small intestine under the circumstances
of this experiment. The antiperistaltic waves of the colon, however,
continue running; the transverse and ascending colon are thus almost
emptied, and the small intestine more and more filled with food (Fig.
9, 2.15 and 3.00). After a short time the typical segmenting movements
can be seen in the loops, busily separating the food into small masses,
and over and over again dividing and redividing them.

I have never seen food material pass back from the colon so far as the
stomach; but once, about ten minutes after an injection of 100 c.c. of
warm water, the cat retched and vomited a clear fluid resembling mixed
water and mucus. In the fluid were two intestinal worms still alive.

The importance of the mechanism by which nutrient enemata are passed
backward in the intestine is evident. In the colon the nutrient
material is worked over by the antiperistaltic waves, intimately
mixed with whatever digestive juices may be present, and exposed to
the organs of absorption in that region. If the enemata are large,
the digestive and absorptive processes are by no means confined to
the colon, but may take place along extensive surfaces of the small
intestine. I have repeatedly seen rhythmic segmentation active
throughout many loops of the small intestine, thus exposing the
injected food to the same mixing and absorbing processes as affect the
nutriment which has come through the stomach in a normal manner.

THE EFFECT OF EMOTIONS AND SLEEP

Observations on the stomach of the cat showed that the peristalsis
is inhibited whenever the animal manifests signs of anxiety, rage,
or distress. Since the extrinsic innervation of a large part of
the intestinal tract is the same as that of the stomach, it is of
interest to note the effect of emotional states on the movements of
the intestines. Esselmont, in a study of the dog’s intestine, noted
constantly after signs of emotion a marked increase of activity lasting
for only a few moments. Fubini also observed that fear occasioned more
rapid peristalsis. There is no doubt that many emotional states are
a strong stimulus to peristalsis, but it is equally true that other
emotional states inhibit peristalsis. In the cat the same conditions
which stop the movements of the stomach stop also the movements of the
intestines.

[Illustration:
FIGURE 10.--Tracings showing the effect of excitement on
antiperistalsis in the colon.]

The female cats used in these observations ordinarily lie quietly on
the holder and make no demonstration. Sometimes, however, with only a
little premonitory restlessness, the cat suddenly flies into a rage,
lashing her tail from side to side, pulling and jerking with every
limb, and biting at everything near her head. During such excitement,
and for some moments after the animal becomes pacified again, the
movements, both of the large and small intestine, entirely cease. Such
violence of excitement is not necessary to cause the movements to stop;
a cat which was restless and continually whining while confined to the
holder showed no signs of intestinal movements during any period of
observation (one period lasted more than an hour), although the changes
in the distribution of the food observable from one period to the next
proved that movements were going on during the quiet intermissions.
In another cat, uneasy and fretful for fifty minutes, no activity was
seen; then she became quiet for several minutes, and peristalsis of the
small intestine appeared.

When the segmentation process in the small intestine is stopped by
excitement the segments unite and the series of parts returns to the
form of a solid string. The change occurring in the large intestine
when the antiperistalsis is inhibited by excitement is shown in Figure
10. The tonic constrictions in the descending colon are apparently not
affected by emotional states, for they do not seem to relax in the
excitement which causes the movements to cease.

By holding the mouth and nostrils closed, or by pressing between the
rami of the jaw, the breathing may be stopped. As soon as the cat shows
distress from lack of breath every form of intestinal movement stops.

The statement is sometimes made in text-books of physiology that the
gastric and intestinal mechanisms cease to act during sleep. It is
worthy of note that nearly all the animals curled up and slept during
the time between observations; nevertheless, the progress of the food
through the intestines continued. The statement is also made that at
night, even without sleep, the intestines are almost entirely at rest;
that this is their normal time for repose. I have seen both large and
small intestines actively at work, however, from half past nine until
half past ten o’clock at night.

SUMMARY

1. Bismuth subnitrate, 10 to 33 per cent, mixed with the food renders
the movement of the intestinal contents, and thereby the movements of
the intestinal walls, visible on the fluorescent screen.

2. The activity most commonly seen in the small intestine is the
simultaneous division of the food in a coil into small segments, and
a rhythmic repetition of the segmentation each time applied to the
new segments formed from parts of those just divided. In the cat this
rhythmic segmentation may proceed at the rate of thirty divisions per
minute. The effects of the constrictions causing the segmentation are
the mixing of the food and the digestive juices, the bringing of the
digested food into contact with the absorbing mechanisms, and the
emptying of the venous and lymphatic radicles of their contents by
compression of the intestinal wall.

3. Peristalsis is usually combined with segmentation. As the food is
advancing, interfering constrictions often separate the rear end of the
mass from the main body. The separation is momentary, however; the
rear end is swept into union with the main body again, and the whole
mass is pushed onward until another constriction repeats the changes.

4. The ileocæcal valve is thoroughly competent for food entering the
colon from the ileum.

5. The usual movement of the transverse and ascending colon and the
cæcum is an antiperistalsis. This recurs in periods about every fifteen
minutes, and each period lasts commonly about five minutes; the waves
recur during a period at the rate usually of eleven waves in two
minutes. This antiperistalsis gives new significance to the ileocæcal
valve; for the food, now in a closed sac, is thoroughly churned and
mixed by the constrictions running towards the cæcum, and again exposed
to absorbing walls without any interference with the processes in the
small intestine.

6. As soon as new food enters the large intestine a strong general
contraction takes place along the cæcum and ascending colon, forcing
some of the food onward; a moment later antiperistaltic waves begin to
pass.

7. With the accumulation of material in the transverse colon, deep
tonic constrictions appear one after another and carry the material
into the descending colon, leaving the transverse and ascending
portions free for the antiperistaltic waves.

8. In emptying the large intestine the material in the lower descending
colon is first carried out by combined peristalsis and pressure of
abdominal muscles; the remainder of the material is then spread into
the evacuated region, and this region is again cleared; the second
remainder may be similarly affected. In normal life the new food
arriving in the colon must force forward the old contents of the
ascending and transverse colon.

9. The observations have revealed no evidence of antiperistalsis in
the small intestine, but since the ileocæcal valve will allow nutrient
material under pressure to pass backward, the antiperistalsis of the
large intestine may force into the small intestine a considerable
portion of a large nutrient enema. Segmentation in the small intestine
affects such an enema precisely as it affects food which has passed
normally through the stomach.

10. Signs of emotion, such as fear, distress, or rage, are accompanied
by a total cessation of the movements of both large and small
intestines. The movements continue in the cat both during sleep and at
night.

THE BATTLE CREEK LABORATORIES

THE MAMMOTH SANITARIUM AND THE LARGE ADOPTED FAMILY OF DR. AND MRS. J.
H. KELLOGG

[A report of one experiment has been selected from _Modern Medicine_
relative to the work of the laboratories connected with the Battle
Creek Sanitarium because it relates to the effect of cooking and
mastication upon food in illustration of the statement of Dr. Campbell
pertaining to these aids to digestion. Much more evidence could be had
from the Sanitarium reports, but sufficient has already been given
herewith from various authoritative sources to justify our claims of
the great importance of mouth-treatment in human nutrition.

It may be said here, however, that the trial of thorough mouth-work as
an aid to digestion, which has been in progress at the Sanitarium for
more than a year, and which has finally been accepted and prescribed
as the first requirement of the treatment of patients, is of the
utmost significance. This is, by far, the largest sanitarium in the
world, having some hundreds of physicians, nurses, and other attachés,
and treating many thousands of patients annually. The “cure” is based
upon natural methods of recuperation, and while all of the staff, both
medical and surgical, are fully equipped diplomatists, and whereas the
organisation has a legally and professionally accepted medical school
of its own, so-called medicines are rarely used, and never except as
antidotes to specific poisons. Nature is assisted by scientific means
to do the curing, and now that an economic nutrition to relieve the
exhausted system of the patient from all possible strain through ample
mouth-treatment of food, as intended by the anatomical, dental, and
chemical plan on which man is constructed, has been tried and accepted
as a fundamental principle of the institution, it gives a practical
indorsement of the claims set forth in “Glutton or Epicure,” and in
this present book, and declares that they are of greatest importance
in securing health and efficiency.

The Battle Creek Sanitarium is a philanthropic and humanitarian
institution operating under a perpetual charter which compels the use
of all the profits gained to foster the spread of the humanitarian
work. More than sixty branches of the parent institution have been
established in or near large cities in different parts of the world,
under the title of The American Medical Missionary Association,
and each of these branches conducts a life-saving business on Good
Samaritan principles. The organisation started its medical missionary
work some thirty-seven years ago, with almost no capital and only
one patient, in a small two-storey frame house, in the then small
village of Battle Creek, Michigan. The incorporators were religious
enthusiasts who believed that Christianity should be expressed in
works as much as in faith, in curing the sick and healing the wounded,
and thus preparing the unfortunate for the reception of moral and
spiritual inspiration.

The best evidence that this scheme of procedure to attain the ultimate
end was a good one is shown by the success of the institution in
its growth from such small beginning to the immense proportions of
the present time, with one of its buildings nearly a thousand feet
in length and five storeys in height and numerous other buildings
radiating from the main one and scattered about it in a finely wooded
park. Fire came and destroyed the old building and all its contents,
but yet it was soon rebuilt, and the concern goes on growing and
growing, because the foundation principle of the institution is the
beautiful Golden Rule, and the method of treatment employed is taken
from the open book of Nature.

While the organisation was primarily based upon a special religious
creedal enthusiasm, it has become so broadly altruistic as to suggest
a return to original Christianity as defined in the Sermon on the
Mount. In such Christian expression honest agnostics, born Buddhists,
and the tolerant of all the different Christian creeds may join and
say amen!

One of the splendid results of an economic nutrition, attained by
following the natural requirements and impulses, is the curing of
many diseases, among them several forms of constipation. The writer
has a genuine admiration for the spirit that is the motive power
of the Battle Creek Sanitarium and firm belief in the Christianity
demonstrated in the work, especially in the private experiment of Dr.
and Mrs. Kellogg, with their family of adopted waifs. Twenty-four
children of unfortunate parents, waifs so unfortunate in their
attractability as to be hopelessly neglected, have been gathered
under this sheltering roof and are showing their mettle and gratitude
by splendid behaviour and brilliant accomplishment in a manner that
any proud parent might approve. To miss any opportunity to express
gratitude to Dr. and Mrs. Kellogg for giving us such a splendid
example of the true meaning of practical Christianity would be showing
symptoms of the worst form of constipation; viz., constipation of
appreciation and affection.—HORACE FLETCHER.]

EXPERIMENTAL INVESTIGATION OF THE INFLUENCE OF MASTICATION AND COOKING
OF FOOD, ETC., IN THE LABORATORIES OF THE BATTLE CREEK, MICHIGAN,
SANITARIUM, UNDER THE DIRECTION OF DR. J. H. KELLOGG

From _Modern Medicine_

The table clearly shows the effect of cooking and the effect of
mastication upon the salivary digestion of food. Column 1 shows the
results obtained after an ordinary test meal consisting of 1½ ounces
of water biscuit to 8 ounces of water; column 2, 1½ ounces of water
biscuit ground fine, mixed with water and swallowed without chewing;
column 3, test meal consisting of 1½ ounces of raw wheat flour and
8 ounces of water; column 4, test meal consisting of 1½ ounces of
unground pearled wheat with 8 ounces of water.

═════════════════════════════════╤════════╤════════╤══════╤══════
│ Water │ Water │ │
│biscuit,│biscuit,│ Raw │ Raw
│ well │ not │flour.│wheat.
│chewed. │chewed. │ │
│ 1 │ 2 │ 3 │ 4
—————————————————————————————————┼————————┼————————┼——————┼——————
Total acidity (A) │ 0.142 │ 0.140 │0.204 │0.136
Calculated acidity (A´) │ 0.156 │ 0.132 │0.186 │0.128
Total chlorine (T) │ 0.296 │ 0.284 │0.332 │0.272
Free HCl (H) │ 0.050 │ 0.028 │0.056 │0.052
Combined chlorine (C) │ 0.106 │ 0.104 │0.130 │0.076
Fixed chlorides (F) │ 0.114 │ 0.152 │0.146 │0.144
Maltose (M) │ 1.088 │ 0.272 │0.000 │0.000
Dextrine and soluble starch (D) │ 0.812 │ 0.548 │0.300 │0.448
│ │ │ │
COEFFICIENTS │ │ │ │
│ │ │ │
Digestion of albumin (_a_) │ 0.82 │ 0.97 │1.00 │1.00
Digestion of starch (_b_) │ 0.71 │ 0.42 │0.00 │0.00
Salivary activity (_c_) │ 1.17 │ 1.11 │1.14 │1.37
Fermentation (_x_) │ 5.00 │ 11.00 │6.00 │6.00
Chlorine liberation (_m_) │ 0.80 │ 0.70 │0.85 │0.71
—————————————————————————————————┴————————┴————————┴——————┴——————

Several points of interest are to be noted in the above table, the
first and most conspicuous of which is the fact that the saliva did
not act at all upon the raw flour and raw wheat, as shown by the total
absence of maltose in the cases represented in columns 3 and 4. The
small amount of dextrine and soluble starch shown was, perhaps, already
present in the raw grain, but this point I have not investigated.
It is clear, however, that no sugar was produced when raw starch was
taken, whereas the amount of sugar produced after the ordinary test
meal was more than 1 gram in each 100 c.c. of stomach fluid; in other
words, the stomach fluid contained more than one per cent of sugar
without taking into account the amount which had been absorbed.

The figures for maltose in column 2 represent a test meal in which
little or no saliva was mixed with the test meal, the food being
swallowed without chewing, indicating very slight action of the saliva,
the amount of maltose found in the stomach fluid being but a trifle
more than one-fourth the amount obtained after an ordinary test meal.
The amount of soluble starch and dextrine was less than half the normal
amount in the case of the raw flour, and but little more in the case of
the raw wheat.

Another point of interest is the increased amount of lactic acid found
in the test meal taken without chewing, represented in column 2. The
coefficient of fermentation which represents the number of milligrams
of lactic acid (as expressed in terms of HCl) found in 100 c.c. of
stomach fluid was more than double that found after the same kind
of test breakfast properly masticated, represented in column 1. The
results of this experiment distinctly associate acid fermentation with
imperfect mastication and imperfect salivary digestion.

Another fact noted in a comparative study of the results of the
analysis of over 5000 stomach fluids, which very strongly confirms
this idea, is that starch conversion is usually complete in cases of
apepsia, while lactic acid is conspicuous by its absence. In nearly all
cases of apepsia which I have encountered, numbering about forty cases
in all, the most delicate tests for lactic acid have failed to show its
presence except in the most minute quantities; in most cases it was
entirely absent.

There are a number of other points of interest in the above table in
addition to those which relate particularly to starch digestion. One of
the most noteworthy of these is the fact that the digestion of albumen
was not unfavourably influenced by the neglect to masticate the food,
the coefficient of digestion, in fact, being raised from .82 to .97.
This coefficient is a qualitative and not a quantitative index. The
higher coefficient indicates a more perfect elaboration of proteids and
a close approach to an absolutely perfect proteid digestion.

Another fact of perhaps even greater interest has relation to the
digestion of albumen when the wheat was eaten raw, in the form of
either flour or wheat. The coefficient of proteid digestion in both
cases, as shown in columns 3 and 4, was 1.00, indicating perfect
elaboration of the albuminoids. From this it appears that raw gluten,
or the proteids of wheat, is digested more perfectly when taken in a
raw state than when cooked, the very opposite of which we have seen
to be true of starch. The digestion of raw starch may take place in
the intestines, by the action of the pancreatic juice, but cannot take
place in the stomach, for the reason that the saliva has not the power
to penetrate the cellulose envelope of the starch granule, and hence
cannot digest raw starch.

This fact coincides in a most interesting manner with the biological
fact that man is by nature a frugivorous animal. In the process of
ripening, the starch of fruits undergoes a hydration similar to that
which takes place in cooking and in pancreatic digestion, whereby
the insoluble starch is converted into soluble starch, dextrine, and
sugar. This explains, also, why well-ripened fruit may be eaten raw
with impunity, while unripe fruit and farinaceous food of all sorts
require cooking. In his diet, man, like his nearest relative, the
monkey, being naturally a frugivorous animal, may eat fruits in the
state in which Nature has provided them; but when he introduces other
natural products into his bill of fare, he must adopt artificial means
for securing the preparation for digestion which Nature makes in the
ripening process of fruits.

The coefficient of chlorine liberation (_m_) is very nearly uniform,
indicating that the mastication of food and the cooking of food have
little influence upon this digestive function.

The coefficient of salivary activity (_c_) was determined independently
for each test breakfast. Its practical uniformity indicates that there
was no essential change in the character or quality of the saliva to
account for the differences shown by the totals in relation to the
stomach digestion of starch.

DR. EDWARD HOOKER DEWEY AND THE “NO BREAKFAST PLAN”

The “No Breakfast Plan,” evolved from the long experimental experience
of Dr. Dewey, to secure much needed rest for the stomach and
intestines, is described in a book bearing that title which can be
had direct from the author by addressing him at his home, Meadville,
Penn., U. S. A.

“No Breakfast” is, evidently, a misnomer, but means, in the present
application, an appetite _earned_ after arising from sleep. The
writer, for instance, often begins work so early in the morning that
by the time the ordinary breakfast is ready he has already done a fair
day’s work.

The writer has no reported details of the work of Dr. Dewey to add
to this volume. In “Glutton or Epicure” full appreciation of this
Esculapian Luther is expressed and extracts of his writings are
reprinted. In fighting for more than forty years for the principle of
less abuse of the tired body of man, Dr. Dewey has rendered a service
that some time will be reckoned very great; and while there is no
scientific report of the good doctor’s work to call for introductory
comment, it would be equally unhealthy to miss an opportunity to
express gratitude for what he has done for us all.

PROFESSOR JAFFA AND THE FRUITARIANS

Professor Jaffa, too, of the University of California, has been doing
most valuable service in testing the usefulness of fruits and nuts as
human foods. He generously furnished the author with elaborate tables
of his results, covering several years of observation, showing low
nitrogen possibilities similar to those demonstrated by the writer and
his colleagues at Cambridge and Yale. These have since been published,
and relating to special kinds of foods, as they do, suggest a wide
range of choice among the fruits of earth; but the collected evidence
of this book shows that human nutrition is best served when the
appetite, being kept at normal, is allowed to make selection from the
whole range of nutritious products furnished by good Mother Nature.

DR. H. P. ARMSBY

In the Oct. 16th, 1903, number of _Science_, also, is an interesting
article by Dr. H. P. Armsby on the heat values and muscular energy
values of different food elements and their isodynamic replacement of
each other under various conditions.—HORACE FLETCHER.]

Explanation of The A. B. C. Life Series

THE ESSENTIALS AND SEQUENCE IN LIFE

It would seem a considerable departure from the study of menticulture
as advised in the author’s book, “Menticulture,” to jump at once to an
investigation of the physiology and psychology of nutrition of the body
and then over to the department of infant and child care and education
as pursued in the _crêche_ and in the kindergarden; but as a matter of
fact, if study of the causation of human disabilities and misfortunes
is attempted at all, the quest leads naturally into all the departments
of human interest, and first into these primary departments.

The object of this statement is to link up the different publications
of the writer into a chain of consistent suggestions intended to
make life a more simple and agreeable problem than many of us too
indifferent or otherwise inefficient and bad fellow-citizens make of it.

It is not an altogether unselfish effort on the part of the author of
the A. B. C. Life Series to publish his findings. In the consideration
of his own mental and physical happiness it is impossible to leave out
environment, and all the units of humanity who inhabit the world are
part of his and of each other’s environment.

It would be rank presumption for any person, even though gifted with
the means to circulate his suggestions as widely as possible, and
armed with the power to compel the reading of his publications, to
think that any suggestions of his could influence any considerable
number of his fellow-citizens of the world, or even of his own
immediate neighbourhood, to accept or follow his advice relative to the
management of their lives and of their communal and national affairs;
but while the general and complete good of humanity should be aimed
at in all publications, one’s immediate neighbours and friends come
first, and the wave of influence spreads according to the effectiveness
of the ideas suggested in doing good; that is, in altering the point
of view and conduct of people so as to make them a better sympathetic
environment.

For instance, the children of your neighbours are likely to be the
playmates of your own children, and the children of degenerate parents
in the slum district of your city will possibly be the fellow-citizen
partners of your own family. Again, when it is known that right or
wrong nutrition of the body is the most important agent in forming
character, in establishing predisposition to temperance or intemperance
of living, including the desire for intoxicating stimulants, it is
revealed to one that right nutrition of the community as a whole is an
important factor in his own environment, as is self-care in the case of
his own nourishment.

The moment a student of every-day philosophy starts the study of
problems from the A. B. C. beginning of things, and to shape his study
according to an A. B. C. sequence, each cause of inharmony is at once
traced back to its first expression in himself and then to causes
influenced by his environments.

If we find that the largest influences for good or bad originate with
the right or wrong instruction of children during the home training or
kindergarden period of their development, and that a dollar expended
for education at that time is worth more for good than whole bancs of
courts and whole armies of police to correct the effect of bad training
and bad character later in life, it is quite logical to help promote
the spread of the kindergarden or the kindergarden idea to include
all of the children born into the world, and to furnish mothers and
kindergarden teachers with knowledge relative to the right nutrition
of their wards which they can themselves understand and can teach
effectively to children.

If we also find that the influence of the kindergarden upon the parents
of the infants is more potent than any other which can be brought to
bear upon them, we see clearly that the way to secure the widest
reform in the most thorough manner is to concentrate attention upon the
kindergarden phase of education, advocate its extension to include even
the last one of the children, beginning with the most needy first, and
extending the care outward from the centre of worst neglect to finally
reach the whole.

Experience in child saving so-called, and in child education on the
kindergarden principle, has taught the cheapest and the most profitable
way to insure an environment of good neighbours and profit-earning
citizens; and investigation into the problem of human alimentation
shows that a knowledge of the elements of an economic nutrition is the
first essential of a family or school training; and also that this is
most impressive when taught during the first ten years of life.

One cannot completely succeed in the study of menticulture from its A.
B. C. beginning and in A. B. C. sequence without appreciation of the
interrelation of the physical and the mental, the personal and the
social, in attaining a complete mastery of the subject.

The author of the A. B. C. Life Series has pursued his study of the
philosophy of life in experiences which have covered a great variety
of occupations in many different parts of the world and among peoples
of many different nations and races. His first book, “Menticulture,”
dealt with purging the mind and habits of sundry weaknesses and
deterrents which have possession of people in general in some degree.
He recognised the depressing effect of anger and worry and other
phases of _fearthought_. In the book “Happiness,” which followed next
in order, _fearthought_ was shown to be the unprofitable element of
forethought. The influence of environment on each individual was
revealed as an important factor of happiness, or the reverse, by means
of an accidental encounter with a neglected waif in the busy streets of
Chicago during a period of intense national excitement incident to the
war with Spain, and this led to the publication of “That Last Waif;
or, Social Quarantine.” During the time that this last book was being
written, attention to the importance of right nutrition was invited by
personal disabilities, and the experiments described in “Glutton or
Epicure; or, Economic Nutrition” were begun and have continued until
now.

In the study of the latter, but most important factor in profitable
living, circumstances have greatly favoured the author, as related in
his latest book, “The A. B.-Z. of Our Own Nutrition.”

The almost phenomenal circulation of “Menticulture” for a book of its
kind, and a somewhat smaller interest in the books on nutrition and
the appeal for better care of the waifs of society, showed that most
persons wished, like the author, to find a short cut to happiness by
means of indifference to environment, both internal and external, while
habitually sinning against the physiological dietetic requirements of
Nature. In smothering worry and guarding against anger the psychic
assistance of digestion was stimulated and some better results were
thereby obtained, but not the best attainable results.

Living is easy and life may be made constantly happy by beginning
right; and the right beginning is none other than the careful feeding
of the body. This done there is an enormous reserve of energy, a
naturally optimistic train of thought, a charitable attitude towards
everybody, and a loving appreciation of everything that God has made.
Morbidity of temperament will disappear from an organism that is
economically and rightly nourished, and death will cease to have any
terrors for such; and as _fear_ of death is the worst depressant known,
many of the _worries_ of existence take their everlasting flight from
the atmosphere of the rightly nourished.

The wide interest now prevalent in the subjects treated in The A. B. C.
Life Series is evidenced by the scientific, military, and lay activity
in connection with the experiments at the Sheffield Scientific School
of Yale University and elsewhere, as related in the “A. B.-Z. of Our
Own Nutrition” and in “The New Glutton or Epicure” of the series.

The general application is more fully shown, however, by the
indorsement of the great Battle Creek Sanitarium, which practically
studies all phases of the subject, from health conservation and child
saving to general missionary work in social reform.

HORACE FLETCHER.

Index

A. B. C. Life Series, the, xxiv, 15, 47;
explanation of, 399-407

Abdominal glands, the, 189, 190

—— muscles, the, 326, 388

—— wall, the, 364

Abernethy biscuit, 131

Acid reaction, of food, 269

Acids, stimulating properties of, 270;
supplement weak action in the stomach, 270;
special relation to the pancreas of, 270

Addison, Joseph, upon the work of Luigi Cornaro, 28

Adenoids, largely dietetic in origin, 148-152, 156

Afferent nerves, special duty of the peripheral terminations of, 184-185

Agriculture, U. S. Department of, 37

Albumen, digestion of, 394

Albuminoids, the, 395

Albuminous foods, minimum amount of, 74, 78

Alcoholic beverages, explanation of the use of, 252

Algarroba bean, the, 124

Alimentary canal, the, 13, 14, 15, 40;
pabulum derived from, 40, 92, 117;
Professor Pawlow’s conclusions concerning, 186;
experimental investigation of the pathology and therapeutics of,
248, 260, 273, 275, 276, 277

Alimentation, human, study of, 13;
theory of, 180

Alkalies, the, 278, 279, 280, 281, 282

Alkaline reduction, 33, 34, 35, 36, 44

—— saliva, 33;
its quantity increased by mastication, 96, 102, 146

Alkalinisation, 92

Altruism, placed upon a business basis, xxiv

American Medical Missionary Association, the, 390

—— Medical Missionary Cause, the, xxiii

—— Physiological Society, the, 68

Anderson, Dr. William G., 54, 87, 88

Anger, causes indigestion, 7

Animal economy, 40

—— food, necessitates less thorough mastication than vegetable, 67,
99-100, 173;
influenced less than vegetable by cooking, 118

—— organism, the efficiency of, 58

Anthropoid apes, 115, 116

Antiperistalsis, 326, 333, 342, 345, 364;
in the colon, 365-370;
the question of, 377-383, 384, 385, 387, 388

Antiperistaltic waves, 365, 367, 373, 374, 376, 381, 383, 387, 388

Antrum, the, 307, 308, 311, 315, 322, 323, 326, 327, 333, 334, 336,
340, 341, 360

Apepsia, 394

Appendicitis, relationship between diet and, 141

Appendix, the, cause of catarrh of, 141

Appetite, demands proteid when wanted, xxxii;
knows what to do and when to do it, xxxiii;
most important factor in digestion, 6;
a perfect indicator, 6;
a creature of the mind, 7;
the caprices of, 7;
easily comprehended, how to read, 8, 9, 12;
an indicator of what the body requires, 20;
will close the valve when enough is eaten, 20;
striking effect of insalivation upon, 50;
fully understood, prevents intemperance in eating or drinking, 95;
sooner satisfied with thorough mastication, 137;
the first and mightiest exciter of the secretory nerves of the
stomach, 210;
is juice, 213;
Dr. Pawlow’s experiment showing value of, 226;
its initial impulse may originate in the stomach, 244;
in the rich and in the poor, 252-253;
care should be taken of, 254;
physicians most often called on to restore, 254;
remarkable how little attention is paid to, 255;
bitters increase, 263, 265;
the strongest of all stimuli to the digestive glands, 263;
connection between gastric juice and, 265.

—— earned, a preliminary necessity of easy digestion, 180

——, false, 6, 9, 29, 75

——, normal, 6

“Appetite juice,” the, 213, 228, 258, 259, 260

Apples, 169

Appreciation, attention necessary to create, 7;
necessary to stimulate flow of digestive juices, 7, 12

Armsby, Dr. H. P., on the heat values and muscular energy values of
different food elements, 397

Asiatics, the, consume smaller proportion of proteids, 82

Asparagus, 93

Astrup, E., 126

Athletes, reason for training, 22

Attention, necessary to create appreciation, 7;
how to command, 8, 9, 12

Atwater, Prof. W. O., 54;
on the daily proteid requirement, 76

—— Respiration Apparatus, the, 57

Australians, the, 118, 129, 163

Bache Fund, the, 69

Bacteria, the action in the intestines of, 39, 117

Bacterial digestion, 40

—— flora, the, examination of, 26

Bacteriology, advances of, 248, 249

Bailey, 128

Balthazard, experiments of, 314, 315, 327, 328

Baltimore, Md., 68

Barling, Gilbert, 141

Barrett, Robert, 47

Bayliss, experiments of, 343, 344, 345, 359

Batter pudding, 98

Battle Creek, Michigan, 390

—— Laboratories, the, 389-391;
experimental investigation of the influence of mastication and
cooking of food, etc., in, 391-396

—— Sanitarium, the, xvii, xxiii, xxvii;
described, 389-391

Bayert, 123

Beans, 95, 132

Beaumont, experiments of, 305, 309, 310, 313, 326, 327, 329, 330, 334,
336

Beef, 100

Benedict, Prof. Francis G., 54

Berlin, 56, 65

Berne, Switzerland, 284

Betel, chewing, 103, 128

Beverages, mastication in the preparation of, 123

Bidder and Schmidt, experiments of, 202, 204, 231;
conditions for success, 204-206

Bile, the, 360

Bitters, therapeutic influence of, 262, 265;
increase the appetite, 263, 264, 265

Blondlot, experiments of, 181, 182, 277

Blood, the, toxins absorbed into, 40;
influence of the contraction of the masticatory muscles on local
circulation of, 107, 148, 149, 278, 355

—— elements, the, 41

Blumfield, Dr. Joseph, 26

Body, the, considered as an engine, 4, 23;
derives its necessary energy from food, 72;
burdened by excess of food, 73

Boer War, the, 11

Bolting food, 35, 36, 134, 135, 138, 140

Bolus, the, 329, 343, 344

Boston Society of Medical Sciences, the, 342

Bouillon, 266

Bowditch, Dr. Prof. Henry Pickering, xxiv, xxv, 67, 68, 70, 284, 285,
287, 306

Bowel, the, liable to suffer, 140, 345

“Bracer,” a, why required, 20

Braun and Grützner, experiments of, 278

Bread, 78, 98, 99, 132, 137, 143, 171, 270, 271, 274, 275

Brinton, experiments of, 329, 330, 334, 336

British Guiana, 124

—— Medical Association, the, 27, 48, 91, 92

“British Medical Journal,” the, 141

Bronchitis, 144, 146

Broth, strong, 268

Brown bread, 43

Brussels, 68

Buccal digestion, 8

—— nerves, the, 194

Bushmen, the, 118, 123

Butter, 43, 100

Cabbage, why indigestible, 99

Cæcum, the, 140, 141, 363, 364, 365, 366, 368, 370, 371, 372, 375,
376, 377, 381, 387

Cake, 132

California, University of, 90, 397

Calm, easy to cultivate, 7

Cambridge, England, xxxi, 26, 47, 49

—— tests, the, 47, 69

—— University, England, xxv, 26, 53, 68, 91

Campbell, Dr. Harry, 8, 12;
on the importance of mastication, 92-179, 389

Cancer, produced by inefficient mastication, 138

Cane-sugar, changed to grape-sugar, 21, 169

Cannon, Dr. W. B., 7, 12;
on “Swallowing and Movements of the Stomach and Intestines,”
284-300;
on the “Movements of the Stomach Studied by means of
the Röntgen Rays,” 301-341;
on the “Movements of the Intestines Studied by Means of the
Röntgen Rays,” 342-388

Carbohydrate foods, 78, 79, 80, 85, 86, 89

Cardia, the, ideas of early writers concerning, 303, 304, 325,
326, 328, 329

Cardiac sphincter, the, 307

Carelessness, the sin of, xvii

Carnegie, Andrew, xxxv

—— Institution, the, 53

Carnivora, the, do not masticate, 97, 161

Cassava root, 124

Cat, the, experiments upon, 289-293, 299, 303, 307, 311, 312, 315,
320, 322, 325, 333, 335, 337-339, 341, 344, 353, 359, 361, 365,
366, 372, 382, 383-386, 388

Catarrh of the appendix, caused by inefficient mastication, 141

Cauliflower, 99

“Cause and Prevention of Decay in Teeth, the,” Wallace’s, 161

Cavendish lecture, Sir Frederick Treves’s, 140

Cell, a, determination of the metabolism of, 40

Cellulose, 117, 170

Cereals, 78, 84, 146

Ceylon, 128

Cheese, 43, 95;
when indigestible, 100, 137

Chemical excitants, the, 268

—— secretion, 259

Chemistry, organic, 62

——, physical, 62

Chewing, length of time necessary for, xxxii

Chicken bone, 166

Chigin, Dr., experiments by, 214, 216, 282

Children, early feeding of, 130-132, 143;
defective mastication in, 148;
feeding of, 262

Children’s Aid Society, the, xxv, 68

Chimpanzee, the, 115

China, 82

Chittenden, Prof. R. H., conducting the experiments at Yale, xvii, 5;
emphasises the want of exact knowledge of nutrition, 53, 67, 68;
the Yale test, 69-91.

Chop bone, 166

Chyme, the, 346, 360, 362

Circulation, the, stimulated by mastication, 96, 103, 157

Cocoa-nut, 137

Coffee, 132

Cole, Sidney W., 47;
his paper upon the isolation of the tryptophane element of the
proteid molecule, 47

Colon, the, 363, 364;
antiperistalsis in, 365-370;
changes when food enters, 370, 371, 372;
process of clearing, 373-377, 381, 382, 384, 387, 388

Comminution, 98, 100, 101

_Commonwealth_, the S. S., 69

Condiments, influence of, 261, 265

Constipation, cannot exist, 43

Constriction, waves of, 323, 340, 341

Cooked flesh, requires mastication, 97, 174

Cooking, influences vegetable more than mineral food, 118;
effect of, 389, 391-396

Cornaro, Luigi, reformed manner of living of, ix;
his autobiography, x, xvi, xvii;
Dr. Van Someren’s paper upon his theory of living, 26-46;
his treatise on the “Sure and

Certain Method of Attaining a Long and Healthful Life,” 28;
Addison’s comments upon his work, 28, 92

Craving for food, 256

Cream, experiments with, 38-39, 43

Cuba, xiv, 70

Curr, E. M., 125, 129

Dastre, Dr. Prof. A., 67, 68

Day, experiments of, 337

Defecation, 373-377

Deglutition, Magendie’s theory of, 284, 285;
movements of, 285;
divided into three parts, 285;
Falk’s and Kronecker’s theory of, 286;
the X-ray method in the study of, 287-295;
phenomena of œsophageal, 298-300

—— reflex, the, 287

Dental caries, causation of, 161

Dewey, Dr. Edward Hooker, and the “No Breakfast Plan,” 396, 397

De Witt, Assistant Surgeon, Lieut. Wallace, in command of soldiers
in the Yale investigation, xiii, 70

Dextrine, 170, 171, 392, 393, 395

Diaphragm, the, 324, 326

Diet, best manner and system of, xiii;
the optimum, xxxi;
minimum, 74;
the anthropoid stage, 116;
the pre-cooking human stage, 117;
the pre-agricultural cooking period, 118;
the early agricultural age, 119;
the late agricultural period, 120;
for children, 130-132;
relationship between appendicitis and, 141

Dietary Ten Commandments, 5

Dietetics, precepts of, 272

Digestion, appetite the most important factor in, 6;
the true chemical end-point of, 10-11;
effect of the mental state upon, 74, 145;
psychic influence in, 180;
the phenomena in, 251;
thorough mouth-work as an aid to, 389

Digestion-ash, the, what it should be like, 10-11, 14;
should not be unclean, 24;
in experiments, 38-39, 42, 43, 47, 51, 79, 83, 84, 85, 94

Digestive activity, stopped by anger and worry, 7

—— canal, the. _See_ Alimentary canal, the

—— glands, the, analogy between the innervation mechanism of the
salivary glands and, 188-190;
appetite the strongest of all stimuli to, 263, 280, 282

—— juices, the, 7;
appreciation necessary to stimulate flow of, 7, 12, 96;
mastication brings the food into intimate contact with, 98;
quantity of, 267;
relation of milk to the secretion of, 274, 383, 386

Digitalis, 281

Diphtheria, 149

Disease, caused by indiscretions in eating, x, xxxi;
follows disobedience, 29

Disobedience, disease follows, 29

Distention, 144

Distress, effect of, 388

Dog, the experiments upon, 181, 194-211, 212-246, 249, 254, 258,
263, 279, 280, 285, 292, 293, 297, 298, 299, 303, 310, 311,
313, 314, 315, 336, 344

Dolomites, the, 26

Drinking, too much, xix, 95

Dry food, 97

Dunn, Miss Eva, 122

Duodenum, the, 303, 315, 356, 360

Dyspepsia, dangers of, xv;
might cease to exist, 35

Eat, how to, 19

Eating, too much, ix;
indiscretions of, x, xix, xxix, 29, 95, 135;
too fast, 20;
systematic inattention to, 259, 260;
English have made a cult of, 261

Economic nutrition. _See_ Nutrition, economic

Efferent nerves, 184, 185

Efficiency, human, the measure of, xxx;
research into causes for, 54

Eggs, experiments with, 38, 43, 78, 95, 100, 137, 277

“Encyclopædia Britannica,” the, 27

Enemata, the, 367, 379, 380, 388

Energy, the minimum transformation of, 59

——, potential, 59

Engine, an, the body considered as, 4, 23

English, the, have made a cult of the art of eating, 261

Emetic, an, 325

Emotion, inhibition of stomach movements during, 337;
effect of, 383-384, 388

Empiricism, medical practice largely based upon, 52

Esquimaux, the, 118, 123, 125, 126

Esselmont, experiments of, 383

Evolution, Nature’s plan of, xi

Ewald, experiments of, 313, 314

Excess, habitual, confirmed by experiments, ix

Excrements. _See_ Digestion-ash, the

Excretia. _See_ Digestion-ash, the

Exercise, necessity of, xxix

Fæces, the, 374. _See also_ Digestion-ash

Falk, Dr., 284;
theory of deglutition of, 286

Fallopius, on the functions of the stomach, 302

Farinaceous food, 395

Fasola, experiments of, 378

Fat, potatoes need not produce, 21, 78, 79, 80, 85, 86, 95, 98, 100;
experiments upon, 271, 272, 274

Faucial tonsils, the, influence of mastication upon, 148

Fear, effect of, 388

Fearthought, 404

Featherman, 123

Fibrin, 276

Flesh food, reduction of craving for, 50

Fletcher, Horace, Dr. Van Someren’s comments upon the case of,
30-31;
his experiments confirmed by Marckwald, 46;
Sir Michael Foster’s comments, 48;
the Cambridge tests, 49-52;
the Middletown test, 54-55, 60;
the Yale test, 75-91

Flour, 132, 392, 393, 395

Food, mal-assimilation of, x;
length of time for chewing, xxxii;
Dr. Kellogg’s estimate of amount habitually used, xxxiv;
mouth-treatment of, 5;
how to masticate and swallow, 8, 9, 31, 32;
actual process of mastication described, 32-34;
important bearing upon the economy of the body of its treatment
in the mouth, 48-49;
its function to supply material from which the body derives
necessary energy, 72;
any excess an incubus, 72-73;
classified under three heads, 78;
in excess, produces a large amount of unnecessary work, 80;
its nutritive value determined by the thoroughness of its
digestion, 79;
softness of, 129;
mastication tends to reduce amount of, 136;
should be eaten with interest and enjoyment, 252;
passionate craving for, 256;
its nutritive value should be considered rather than taste, 261;
the acid reaction of, 269;
relative nutritive values of different, 275, 276;
experiments upon the utilisation of, 275;
effect of the movements of the stomach upon, 328;
circulation of, 329;
experimental investigation of the influence of mastication and
cooking of, 389-396

Foster, Sir Michael, xxiv, xxv, 26;
his note upon Dr. Van Someren’s paper, 48-52;
emphasises the want of exact knowledge of nutrition, 52, 53, 67,
68, 91

Fowls, experiments upon, 299

Fruitarians, the, 90, 397

Fruit sugar, 169

Fruits, 43;
under-ripe and over-ripe, 141, 395, 396;
usefulness of, 397

Fubini, experiments of, 383

Fundus, the, 317, 322, 323, 324, 325, 330, 333, 334, 335, 336, 337,
340

Galen, on the functions of the stomach, 302

Gastric catarrh, 249

—— digestion, 309, 316

—— glands, the, 182;
the vagus and the sympathetic nerves exciters of, 183, 198;
mechanical and chemical stimulation of the cavity of the mouth
has no effect on, 201;
psychic excitation of, 205;
sleep exercises no restraining influence upon, 206;
the simultaneous excitation of the different sense organs the
first and strongest impulse toward activity of, 210;
psychic secretion the normal commencement of secretory activity
on the part of, 214;
conditions upon which depends the secretory work of, 227;
mechanical stimulation of, 237, 245, 249, 271, 272, 274, 280

Gastric juice, the, appreciation necessary to stimulate flow of, 7;
destroys micro-organisms, 41;
its flow increased by mastication, 102, 146;
secretion of, 181, 206, 208, 211, 213, 262;
connection between the appetite and, 265, 266;
experiments for, 267;
too little, 270, 272, 273;
salts of sodium promote a flow of, 277, 279, 280, 329, 334, 335,
337, 340, 341

—— mechanism, the, 385

—— movements, the, 301;
early writings on subject of, 302;
later experiments upon, 303, 327, 329, 338

—— mucous membrane, the, excitability of, 181, 231, 241, 249, 258,
259, 264

—— muscular fibres, the, 307

“Gastric tonics,” 255

Gastritis, inefficient mastication may produce, 138

Gastro-intestinal catarrh, 144

Gastronomic enjoyment, increased by proper mastication and
insalivation, 22

Germany, food in, 267

Ginger, preserved, 141

Gladstone, William E., his theory of mastication, 92

Gland metabolism, 277

Glinski, Dr., 190, 194, 196, 197

Gluten, raw, 395

“Glutton or Epicure,” 26, 31, 92, 389, 396.
_See also_ “New Glutton or Epicure, The”

Goose, the, experiments upon, 288

Goose-fat, 100

Gorilla, the, 115

Gran Chaco Indians, the, 123

Grape-sugar, chemically made from cane-sugar, 21, 169

Greens, 132

Grey, Sir George, 128

Griddle-cakes, need not be hurtful, 21

Griffin, Charles & Company, 180, 181

Grützner, experiments of, 278, 346, 363, 377, 378, 381

Gscheidlen, 235

Guinea-pigs, experiments upon, 39

Gum arabic, chewing, 103

Gustatory indifference, 263

—— nerves, the, 263, 269

Gut, the, 344, 345, 355, 360, 364, 365, 374

Hæmorrhoids, cannot exist, 43

Haller, experiments of, 304;
his summary of the motor functions of the stomach, 304-305, 309

Harvard Medical School, 68

—— Physiological Laboratory, the, 284

Haste, danger of, 134-135

Headache, produced by inefficient mastication, 138

Health, the optimum, xxxi

Hearing, the sense of, 210

Heart, the, stimulated by mastication, 96, 103, 281

Heartburn, 144

Heat values, 397

Heger, Dr. Prof. Paul, 67, 68

Heidenhain, 181, 182, 183, 235

Herbivora, the, practice thorough mastication, 97

Higgins, Dr. Hubert, letter from, xxvii-xxxiii, 47

Hirsch, experiments of, 305, 315

Hofmeister, experiments of, 305, 308, 309, 310, 311, 313, 314, 326,
327, 332

Hopkins, Dr. F. Gowland, 26;
his paper upon the isolation of the tryptophane element of the
proteid molecule, 47

_Hors d’œuvre_, 266

Horse, the, experiments upon, 293, 294, 300

Hospital Corps, the, at New Haven, xiii, 70

Hunger, 241;
“the best sauce,” 254

Hyperacidity, 145

Hyperæmia, 345

Hyperchlorhydria, 144, 147

“Igniting juice,” 260

Ignorance, dietic, sin of, xvii

Ileocæcal valve, the, 355, 362;
the competence of, 362-364, 367, 370, 376, 381, 387, 388

Ileum, the, 363, 364, 367, 370, 382, 387

India, 82, 128

Indians of Honduras, the, 124

—— of Nicaragua, the, 124

—— of North California, the, 122, 126

Indigestion, x;
dangers of, xv;
caused by anger and worry, 7;
“bunching hits” to oppose, 13-16

Indol, the odourous, 47

Industries, the, mastication in, 124

Infant life, action of saliva in, 36

Innervation mechanism, an, constituent parts of, 184

Insalivation, defined, 8, 22;
increases gastronomic enjoyment, 22, 46, 48;
its striking effect upon appetite, 50, 60;
effects of, 74, 89, 92, 93, 96;
mastication promotes, 101

Insane, the, forced feeding of, 268

Instinct, human, the outcome of every-day experience, 251;
physiology merely confirms the precepts of, 251;
provisions for digestion made by, 267;
demands of, 272

Intemperance, 95

International Congress of Physiologists, the, 26, 48, 56, 68, 91

—— Laboratory of Research, the, proposal to found, 55-69;
suggestions as to staff and personnel, 62;
estimate of initial outlay, 63;
suggestions as to location, 63;
suggestions as to management, 66

Intestinal anæmia, 345

—— canal, the, 39, 346

—— contents, the, rhythmic segmentation of, 347-355, 386

—— digestive juices, the, 361

—— mechanism, the, 385

—— movements, difficulties of investigating, 342;
the best known of, 343

—— secretion, 61

—— wall, the, 344, 381, 386

Intestine, the large, activity of, 343;
movements of, 364-377, 379, 386, 387, 388

——, the small, 343, 346;
the movements of, 347-362, 366;
course of food in, 360-362, 365, 367, 369, 378, 381, 383, 385,
386, 387, 388

——, the, action of the bacteria in, 39;
micro-organic action in, 40, 80, 92;
much more sensitive than the stomach, 139, 301, 317, 328, 337,
341;
studied by means of the Röntgen rays, 342-388, 395

Jaffa, Professor, 90;
and the fruitarians, 397

Japan, 82

Jaws, the, mastication stimulates the nutrition of, 96, 103, 155;
influence of mastication upon, 109, 148;
changes during man’s evolution in, 115-121;
instances of vigorous use, 122

Johns Hopkins University, 68

“Journal of Physiology, The” (American), 284, 301, 342

—— (English), 47

Kais Root, 123

Kane, Dr., 125

Kara, 124

Katabolic action, 41

Katabolism, 95

Kellogg, Dr. J. H., xxvii;
letter from, xxxiii-xxxv;
his estimate of amount of food habitually used, xxxiv;
tribute to, 391;
his experimental investigation of the influence of mastication
and cooking of food, 391-396

—— Mrs. J. H., 389;
tribute to, 391

Kelp, 122

Kotljar, experiment by, 217

Kreuznach, 46

Kronecker, Dr. Prof. Hugo, 67, 68, 284, 285;
theory of deglutition of, 286

Kumagawa, experiments of, 81

_Kwas_, 267, 269, 270

Lactic acid, prepared in the stomach, 269, 393, 394

“Lancet, The,” 8, 26, 31;
Dr. Campbell’s articles from, 92-179, 145

Lard, 272

Laws of Nature, health, strength, and moral tone dependent upon
proper fulfilment of, 73

Leonardi, Dr. Professor, 26

Life, right conduct of, xiii;
the essentials and sequence in, 399

Lippincott, J. B. & Company, 180, 181

Liqueurs, 266

Liquids, how to treat, 9, 34, 93, 94, 95

Lobassoff, Dr., experiments by, 217, 218, 220, 222, 226

Lobster, 137, 141

London, 65

Lower Californians, the, 123

Ludwig, experiments of, 342

Lumen, the, 374

Lymph, influence of the contraction of the masticatory muscles on
local circulation of, 107, 148, 149, 355

Macaroni, 132

—— cheese, 100

Mackerel, 141

Madrid, 69

Magendie, theory of deglutition of, 284

Maize, chewed, 124

Mal-assimilation, of nutriment, x, xxi;
“bunching bits” to oppose, 13-16;
dangers of, 24, 35

Malay, 128

Mall, experiments of, 343, 345, 354, 378

Mal-nutrition, causes of, xxi, 35

“Malt extracts,” 102

Maltose, starch turned into, 101, 170, 392, 393

Man, the First Assistant of Nature, xi;
his disparity due to ignorance, xii;
absurdity of his ignorance, 4, 23;
experiments upon, 300;
by nature a frugivorous animal, 395

Maple sugar, 84

Marckwald, Max, paper “On Digestion of Milk in the Stomach of
Full-grown Dogs,” 46

Masticate, how to, 19

Mastication, inefficient, causation of, 129;
must lead to many evils, 129;
evils resulting from, 135;
conduces to excessive eating, 135;
may cause suffocation, 137;
may produce gastritis, 138;
excess of starch may pass into stomach because of, 141;
prevents a sufficient amount of alkali to pass into the stomach,
146;
causes evils with the jaws and their appendages and the adjacent
structures, 148;
responsible for adenoids, 148-152;
a potent cause of Rigg’s disease, 159;
secondary evils of, 164, 394

——, proper, increases gastronomic enjoyment, 22, 46, 48, 60;
effects of, 74, 89;
Dr. Campbell’s observations upon, 96-173;
the effects of, 96;
primary object of, 96;
promotes flow of saliva, 96, 101;
stimulates the heart and circulation, 96, 103;
influences the nutrition of the jaws, 96, 103;
facilitates swallowing, 97;
brings the food into intimate contact with the digestive juices,
98;
increases amount of alkaline saliva passing into the stomach, 96,
102;
acts reflexly upon the stomach, 102;
the muscles of, 104;
its influence upon the jaw-bones, 109;
its influence upon the teeth, 110;
in the preparation of beverages, 123;
in the industries, 124;
the instinct of, 126;
the causation of inefficient, 129;
less opportunity than formerly for, 130-133;
defective apparatus for, 133;
affected by individual differences, 134;
tends to diminish amount of food consumed, 136;
most effective way to secure starch digestion, 145;
effect upon the nasal passages, naso-pharynx, and faucial tonsils,
148;
fast becoming a lost art, 157;
means of insuring adequate, 164, 389;
experimental investigation of the influence of, 391

Masticatory instinct, the, 126-129

—— muscles, the, 104;
influence of their contraction on local circulation of blood and
lymph, 107, 148

Matri, 128

Meadville, Penn., 396

Measles, 149

Meat, 78

—— broth, 266;
an important chemical excitant of gastric secretion, 266, 267

—— extract, 268

—— juice, 268

Mechanical stimulus, great importance assigned to, 257

Medical practice, largely based upon empiricism, 52

—— science, not possessed of final information concerning questions
of nutrition, 52

Medicine, ideal only when it can take its proper position, 249;
physiology can make no pretence to guide the field of, 251;
to what it will at length grow, 251;
treats too lightly the loss of appetite, 256

Melanesia, 128

Melanesians, the, 120

Meltzer, Dr., 284;
experiments of, 294, 296, 297, 298

Mendel, Dr. Lafayette B., 69

Mendel Pass, _bei_ Bozen, Süd Tirol, Austria, experiments at, 26

Mental energy, 41

—— state, 12;
its effect upon digestion and nutrition, 74

Menticulture, physical and mental equipments necessary to promote,
7

“Menticulture,” xxi, xxiv

Metabolism, 37;
determination of, 40;
calorimetric trial-balance measurement of, 54

Micro-organisms, 40;
destroyed by acid gastric juices, 41

Middletown, Conn., experiments at, 54

Milk, how to drink, 9;
experiments in drinking, 36, 38-39, 78, 84, 93, 94, 268;
takes a special position among foods, 272;
the three properties of, 273;
its relation to the secretion of the digestive juices, 274, 275,
276, 277

—— pudding, 97, 143, 172

“Modern Medicine,” 389, 391

Modoc Indians, the, 123

Moist foods, 97

Moritz, experiments of, 324, 328, 332

Mosso, Dr. Prof. Angelo, 67, 68, 284, 285

Mouth, the, should do all it can, 93, 180;
examination of, 174-179;
rinsing, 179;
mechanical and chemical stimulation of the cavity of, 201, 285,
286

—— breathing, evils of, 151-153

—— discrimination, 94

—— thoroughness, 8

—— treatment, of food, 5, 12, 92;
a preliminary necessity of easy digestion, 180, 389

Mucosa, the, 343, 355

Mucous membrane, the, 346

Munich, 56, 76, 81

Muster, 128

Mutton, 100

Nansen, J. F., 123
[36]
Napoleon, died from fast eating, 138

Nasal passages, the, effect of mastication upon, 148

Naso-pharyngitis, 144, 148, 149

Naso-pharynx, the, influence of mastication upon, 148

National Academy of Sciences, the, contribute to fund for research,
69

Natural Automatic Processes, 3, 180

Nature, plan of evolution of, xi;
Man the First Assistant of, xi;
her reward for conformity with her requirements, xii;
her generous assumption of forty-seven forty-eighths of labour, 5,
12;
given an opportunity by economic nutrition, 22;
her plans perfect if her laws are obeyed, 29;
never intended a special diet or bottle of medicine, 30;
endeavours to prepare lactic acid in the stomach, 269

Negritos, the, 118

Negroes, the African, 120

Nerve cells, the, specific qualities of, 187

—— fibres, 184

Nervous system, the, influence upon the glands of, 183

Neutralisation, 92

“New Glutton or Epicure,” the, xxviii, 47.
_See_ also “Glutton or Epicure”

New Guinea, 124

New Haven (Conn.), scientific experiments at, xiii, 54, 71.
_See_ Yale investigation, the, and Yale test, the

Nitrogen, 85, 86

Nitrogenous equilibrium, 86

—— measurements, tests of, 26

“No Breakfast Plan,” the, 396

Nothnagel, experiments of, 343, 345

Northwest London Hospital, the, 8, 92

Nutarians, 90

Nutrient enemata, 367, 379, 380, 382, 388

—— fluid, 381

Nutriment, selection of, 7

Nutrition, economic, experiments upon problem of, ix, x, 48-52;
active interest now taken in, x;
the financial saving the least of the profits in, xi;
the key to England’s welfare, xxv;
attitude of the scientific mind towards, xxvii;
little accurate knowledge concerning, xxx;
psychology of, 6-7;
appetite the most important factor in, 6;
mechanical and chemical physiology of, 8;
its entire principle simple and practical, 19;
does not advise avoiding starchy foods for stout people, 21;
assures that the same food will add or decrease weight, 21;
keeps one in perfect condition, 22;
its requirements not hardships but pleasures, 22;
not a joke or fad, 24;
an appeal to self-examination and self-instruction, 24, 25;
first scientific recognition of principles of, 26;
medical science not possessed of final information concerning
questions of, 52;
plan for institution of an international inquiry into the subject
of, 53-55;
proposed to found an international laboratory of research for the
study of, 55-68;
no question of greater importance, 72;
poverty and vice traced to perversion of, 73;
great need of thorough physiological study of, 74;
effect of the mental state upon, 74

Nutrition, animal, 56, 57, 58

Nutritive equilibrium, 37;
experiments in, 37-39

Nuts, 141, 173;
usefulness of, 397

Nuttall, Dr. George H. F., 26, 39, 47

Œsophagus, the, may protect the stomach, 139, 192, 285, 286, 289,
291, 292, 297, 299, 300, 303, 304, 307, 316, 325, 326, 336, 341

Openchowski, experiments of, 305, 325

Orang, the, 115

Oranges, 169

O’Reilly, Surgeon-General, xvii, 69, 70

Ozawa, Professor, 55

Pabulum, the, derivation of, 40, 41

Pacific Islands, the, 124

Padua, Italy, 28

Palate, the, “the dietetic conscience,” 75

Pancreas, the, excited by the vagus and the sympathetic nerves, 183,
270;
special relations of acids to, 270, 271, 273, 274, 279

Pancreatic digestion, 395

—— gland, the, 269, 270, 271, 280

—— juice, the, experiments for, 267, 270, 273, 279, 360, 395

Paris, 56, 65

Pastry, 132, 172

Patagonians, the, 128

Pathology, 249

Pavia, University of, 26

Pawlow, Dr. Prof. J. P., 6, 7, 12;
researches of, 61, 67, 68;
his demonstrations of psychic influence in digestion, 180-283

Peas, 132

_Pendelbewegung_, the, 342

Pendulum movement, the, 358-360

Penegal, xxxiii

Peptic digestion, 318, 335

Peristalsis, 327, 330, 333, 337, 340, 343, 344, 346, 348, 355-357,
361, 365, 377, 378, 383, 384, 386, 388

Peristaltic wave, the, 343, 353, 365

Pflüger’s Archives, 182

Pharynx, the, 285, 286, 290, 298

Philippines, the, 69

Physicians, most of them called on to restore appetite, 254;
their indifference to appetite, 257;
in Russia, 260;
should bear in mind the question of psychic secretion, 261

Physiology, applied, 251

Pine-apple, 141

Pitcherie, chewing, 129

Polynesia, 128

Poorer classes, the, appetite stronger among, 253;
food of, 266, 267

“Popular Science Monthly, The,” xxxiii, 53;
Professor Chittenden’s article in, 69-91

Pork, 100, 141

Porridge, 97, 143, 172, 270

Potato, made digestible by saliva, 20;
if masticated, need not produce fat, 21;
experiments with, 38, 102;
yields abundant sugar by long-continued mastication, 142, 146

Potatoes, boiled, 143, 172

Poverty, traced to perversion of nutrition, 73

Proteid, demanded by the appetite, xxxii;
the putrid decomposition of, 47;
minimum amount of, 74, 78, 79;
Asiatics consume smaller proportion of, 82, 83, 85, 98, 100, 272,
394

——, the high, xxxii, xxxiii

——, the low, xxxi, xxxii, xxxiii

—— digestion, perfect, 394, 395

—— molecule, the, isolation of the tryptophane element of, 47

Physiology, experimental, 249;
can make no pretence to guide the field of medicine, 251;
merely confirms the precepts of instinct, 251

Psychic environment, 12

—— excitation, 259

—— influence, in digestion, 180-283

—— juice, the, 213, 257, 267

—— secretion, 261

—— stimulation, 249

Pultaceous foods, 95, 97

Pyloric sphincter, the, movements of, 314

Pylorus, the, stands guard over the intestines, 139, 141;
observations of Fallopius upon, 302;
ideas of early writers concerning, 303;
later experiments, 304, 307, 308, 315, 316, 317, 325, 326, 328,
330, 331, 332, 333, 340, 341, 360

Rabbit, the, experiments upon, 344, 359, 371

Rage, effect of, 388

Raiser, experiments of, 359, 371

Rectal injections, stimulating effect on movements of small
intestine of, 367

Rectum, the, 374, 379, 382

Reed, Dr. Major Walter (martyr to science), 70

Regina Margherita Laboratory, the, summit Monte Rosa, 64, 68

Regurgitation, 35

Rhinitis, 144, 148, 149

Rhythmic segmentation, of the intestinal contents, 347-355, 358,
360, 362, 383, 386

Rice, 82, 132

Rickets, 144

Rigg’s disease, 159, 163

Rjasanzew, Professor, experiments of, 275

Roberts, Sir William, 75, 147

Rockefeller, John D., xxxv

—— Institute of Preventive Medicine, the, 68

_Rollbewegung_, 345

Röntgen rays, the, Dr. Cannon’s studies with, 180, 284, 287-300,
301-341, 342-388

Roosevelt, President Theodore, 70

Root, Secretary of War, Elihu, 70

Rosa, Monte, 64, 68

Rossbach, experiments of, 305, 309, 311, 313, 314

Roux, experiments of, 314, 315, 327, 328

Royal Society, the, 68

Rumination, 35, 98

Russell, Dr. William, 145

Russia, physicians in, 260;
food in, 267, 272

Russian Imperial Military School of Medicine, the, 68

—— peasant, the, 270

Sabbatani, experiments of, 378

St. Martin, Alexis, investigations on, 305, 309

Saliva, its chemical effect upon potato, 20;
upon syrup, 21, 33, 34, 35;
its action in infant life, 36;
an important therapeutic agent, 45, 93, 94, 95;
mastication promotes flow of, 96, 101;
dry food produces greater flow than moist, 97, 147;
complicated physiological functions of, 191-192, 337, 392, 393,
395, 396

Salivary digestion, in the stomach, 335, 341;
effect of mastication and cooking of food upon, 391;
imperfect, 394

—— glands, the, 155;
analogy between the innervation mechanism and the glands of
digestion, 188-190;
the exciting agencies of the nervous mechanism of, 191;
their particular properties, 191-194;
differences between the exciting agencies of the different,
194-198;
Professor Pawlow’s sham-feeding experiment, 198-211, 280

—— secretion, excitants of, 191

Sapidity, 44

Sauces, 269

Schäfer, 40, 82

Schmidt, experiments of, 202, 204, 231;
conditions for success, 204-206

Schütz, experiments of, 305, 308, 309, 310, 311, 313, 314, 327,
332

Schwartz, experiments of, 303, 304

Scientific Assessors, Board of, 67, 68, 181

Secretions, digestive, 180

Secretory fibres, 183

—— nerves, 266

Segmentation, 386, 388

Selection, of nutriment, 7

Self-nutrition, secret of, xii

Sensory nerves, 187

Sham feeding, experiments in, 198-211, 214-246;
psychic effect may become an absolute and independent factor in,
209, 279

Sheffield Scientific School, the, experiments at, 53, 68

Sight, the sense of, 210

Sivén, experiments of, 81

Skatol, the odourous, 47

Sleep, exercises no restraining influence upon the gastric glands,
206;
effect of, 383-386

Smell, the sense of, 210

Snyder, Dr., experiment in nutritive equilibrium, 37-38

Société de Biologie, the, 46

Sodium, salts of, 277;
promote a flow of gastric juice, 277, 278, 279, 281, 282

Soft foods, 97, 129, 136, 142, 160, 162

Solid foods, 94, 268

Solray Sociological Institute, the, 68

Sorbonne, Universitie de la, 68

Soups, 266, 267

South Africa, 11

—— America, 124

“Spectator,” the, 28

Sphincter, the, 315, 316, 317, 331, 333, 341

Spinach, 99

Spirits, 93, 94

Ssanozki, Professor, experiments of, 203, 228

Starch, needed by body, 20, 21, 78, 98;
changed into maltose, 101, 102;
danger to the stomach in receiving an excess of, 141-146;
the last constituent to leave the stomach, 145, 170, 171, 172,
270, 337, 393, 395, 396;

Starling, experiments of, 343, 344, 345, 346, 359

Stews, 266

Stomach, the, struggles bravely to overcome abuse, 19;
man’s ignorance concerning requirements of, 23;
mastication acts reflexly upon, 102;
a long-suffering organ, 138;
its danger of receiving an excess of starch, 141;
starch the last constituent to leave, 145;
necessity of alkali in, 146;
secretory work of, 182, 183, 229;
secretory nerves of, 210, 227;
the seat of certain definite sensations, 241;
the initial impulse towards awakening an appetite may originate
in, 244, 246;
no material progress in the physiology of, 250;
Nature endeavours to prepare lactic acid in, 269;
acids supplement weak action in, 270, 279;
catarrhal affections of, 280;
gives no obvious external sign of its workings, 301;
studied by means of the Röntgen rays, 301-341;
Galen’s observations on the functions of, 302;
Fallopius’s views upon, 302;
the motor functions of, 304;
the anatomy of, 306;
its relations to the shadow, 306;
the musculature of, 308;
normal movements of, 309;
the peptonising function of, 314;
its appearance at various stages of digestion, 319;
composed of two physiologically distinct portions, 324, 340;
its movements in vomiting, 325;
effect of its movements upon the food, 328;
attempts to perform function of teeth, 333;
salivary digestion in, 335;
inhibition of its movements during emotion, 337

—— fluids, 393, 394

Suffocation, caused by inefficient mastication, 137

Sugar, 21, 78, 89, 95, 169, 337, 393, 395

Sugar-cane, 123, 124, 169

“Sure and Certain Method of Attaining a Long and Healthful Life,”
Luigi Cornaro’s treatise upon, 28

Swallowing, facilitated by mastication, 97;
mechanism of, 284.
_See also_ Swallowing Impulse, the

—— Impulse, the, xxxii, 8, 9, 93, 94

—— reflex, Dr. Van Someren’s, 26, 44

Sweet potato, 124

Sweets, why pleasant, 268, 269

Sympathetic nerve, the, an undoubted exciter of the gastric glands
and of the pancreas, 183

Syrup, chemical effect of saliva upon, 21

Tapioca, 132

Taplin, 125

Tasmanians, the, 122

Taste, delicacy of the sense of, 22, 23;
should be dissipated in the mouth, 93, 210;
necessary to give an impulse to the organs of, 253;
the nutritive value of food should be considered rather than,
261

—— gratification, 93

Tea, 132

Tea-taster, the professional, methods of, 23, 93

Teeth, the, influence of mastication upon, 110;
changes during man’s evolution, 115-121;
instances of vigorous use, 122-126;
irregularity in, 156;
evils of imperfect use of, 157;
examination of, 174-179;
the

stomach attempts to perform function of, 333

“Text-Book of Physiology,” Schäfer’s, 40

“That Last Waif: or Social Quarantine,” xxv

Therapeutic experiments, pathological, 249

Therapeutics, precepts of, 272

Thierfelder, 39

Thirst, 95

Thompson, Dr., 142

—— Prof. W. H., 180, 181

Thorax, the, 290

Tobacco-chewing, 103, 129

Tokio, University of, 55

Tongue, the, needs exercise, 154

Tonic constrictions, the, 344;
the appearance of, 370-373, 385, 387

—— rings, the, 373

Tonsillitis, 144, 148

Tooth-brush, the, 177

Tooth-powder, 178

Toxins, absorbed into the blood, 40, 41, 44, 143

Training, for athletes, why necessary, 22

“Traité Analytique de la Digestion,” Blondlot’s, 181

Treves, Sir Frederick, on bolting of food, 140, 141

Trinity College, Dublin, 180

Trophic fibres, 183

Tryptophane, 47

Tuberculosis, 144

Turin, Italy, Congress of Physiologists at, 26, 48, 56, 91

——, University of, 68, 284

Urine, should be inoffensive, 42, 93, 274

Vagus nerve, the, an undoubted exciter of the gastric glands and
of the pancreas, 183;
its functions almost interminable, 183, 249

Van Someren, Dr. Ernest, xxv, 7, 12;
his paper “Was Luigi Cornaro Right?” 26-46;
his swallowing reflex, 26, 44;
his experiments confirmed by Marckwald, 46;
Sir Michael Foster’s Note upon his paper, 48-52;
the Cambridge tests, 49-52, 53, 60, 91, 92, 98

Van Valzah, 146

Veal, 100

Veddahs, the, 128

Vegetable food, experiments with, 40;
necessitates more thorough mastication than animal, 97, 98, 173;
influenced more by cooking than animal, 118, 132, 170

Vegetables, 43, 78

Venice, Italy, 30, 63, 64, 91

Vermicelli, 132

Vermicular contraction, 343

—— wave, the, 345

Vermiform appendix, the, 140

Vice, traced to perversion of nutrition, 73

Vienna, 65

—— bread, 131

Vinegar, 269

Vivisection, 303, 305

Voice, the, requires lusty exercise in youth, 149

Voit diet, the, 76, 81, 84, 86

Vomiting, the act of, 193, 303;
movements of the stomach in, 325, 341

Wallace, Dr. G. Sim, 110, 113, 130, 154, 158, 161, 169, 174, 177

Walther, Dr., experiments of, 267, 276

Washington, D. C., 70

Water, how to drink, 9, 34, 95, 268, 391, 392

—— biscuit, 391

Weight, must become normal, 43

Welch, Dr. Prof. William H., 67, 68

Wepfer, experiments of, 303, 304

Wheat, unground pearl, 392, 393, 394

—— flour, 392

Wine, how to take, 9, 22, 23

Wine-tasters, the professional, methods of, 23, 93

Wolves, experiments upon, 303

Wood, Maj. Gen. Leonard, 69, 70

Worry, causes indigestion, 7

Wulfson, Dr., 197

X-ray. _See_ Röntgen ray

Yale investigation, the, x, xi, xiii-xv, xvii, xviii, xix, xxxiii

—— Gymnasium, the, 87

—— test, the, 5, 69, 75-91

—— University, 68

Z, in the nutrition alphabet, 10, 12;

Zuntz, Dr. Prof. N., 67, 68

FOOTNOTES:

[1] Appetite alone can judge accurately of the former, and the true
Swallowing Impulse is the limitation of the latter. If we study the
natural instincts, the rest will take care of itself.

[2] This is very strong evidence that appetite knows what to do and
when to do it, if you study and consult it and give it a chance to
prescribe.

[3] The Yale test reported herein by Professor Chittenden showed the
possibility of full alimentation according to the requirements of
Economic Nutrition in from 24 to 26 minutes daily, which is less than
1∕48 of a day. Beginners of the practice of careful mouth-treatment
of their food _may_ require more time, but, whatever it may be, it
is worth it. A little care for a short period will establish a right
habit, and then no further tedious attention nor unusual time will be
necessary to accomplish a perfectly healthy nutrition.

[4] Physiological Economy in Nutrition: The Frederick A. Stokes
Company, New York.

[5] William Heinemann: London.

[6] The author is not yet permitted to publish the particulars of these
reforms in process, but he has official information regarding them and
is in full sympathy with them.

[7] Dental surgeons now speak of the upper jaw as the maxilla, and of
the lower jaw as the mandible.

[8] This subject I am obliged to deal with very briefly, and am
compelled to omit the reasons for my conclusions.

[9] Recent observations go to show that man possesses no power of
digesting cellulose, though this substance is to a limited extent
capable of solution by the agency of bacteria in the lower portions of
his alimentary canal.

[10] I am under great obligation to Miss Eva Dunn, who has collected
valuable information for me on this and kindred subjects.

[11] Social History of the Races of Mankind, 1881.

[12] S. Powers: Tribes of California, 1877.

[13] E. M. Curr: The Australian Races, 1886-7. Taplin: The Narrinyeri;
an account of Tribes of South Australian Aborigines, 1879.

[14] J. F. Nansen: Eskimo Life, 1893.

[15] Dr. Kane: Arctic Exploration, 1854.

[16] E. Astrup: With Peary near the Pole, 1898.

[17] Sir George Grey: Journal of Two Expeditions in North-West and
Western Australia, 1841.

[18] Muster: With the Patagonians, 1869.

[19] Bailey: Transactions of the Ethnological Society, 1862.

[20] E. M. Curr: The Australian Race, 1886-87.

[21] The Causes and Prevention of Decay in Teeth, pp. 88, 89. London,
1902.

[22] Gilbert Barling also traces the relationship between appendicitis
and diet. “In a considerable number of cases,” he writes, “the attack
of appendicitis can be directly attributed to unsuitable food--pork,
mackerel, over-ripe or under-ripe fruit, uncooked vegetables” (Brit.
Med. Jour., vol. i., 1903, p. 61).

[23] My friend, Dr. Thompson, undertook, at my suggestion, some
experiments to test the digestibility of raw starch within the mouth;
he found that raw potato yields abundant sugar when subjected to
long-continued mastication.

[24] _The Lancet_, March 21st, 1903, p. 806.

[25] Brit. Med. Jour., Epitome, vol. i., 1903, p. 45.

[26] A further aid to the circulation in the naso-pharynx is afforded
by the lusty use of the voice. It a natural for the young human to cry
and to shout, and unless this instinct is allowed full play the child
is apt to suffer in health. I cannot but think that the modern child
is too much repressed in this respect, and that he is not afforded,
especially in towns, proper opportunity of venting his vocal energy
in out-door play. May we not have here a contributory factor in the
causation of adenoids?

[27] Among the Australian skulls I have examined in museums caries
of the wisdom teeth--_i.e._, in those very teeth which, as shown by
their atrophy, are least used--is by no means uncommon (though it is
possible that some of the skulls belong to natives who have embraced
the dietetic customs of the white man). I submit that this fact may
fairly be used as an argument in favour of the view that inefficient
use of the teeth predisposes them to caries by interfering with their
resisting power, though it must be acknowledged that the position of
the wisdom teeth places them at a disadvantage, owing to the tendency
of food to accumulate about them, especially in undeveloped jaws in
which they have not adequate room.

[28] This film can be felt by the tongue as a somewhat rough covering,
which gives place to a smooth surface after the use of the tooth-brush.

[29] By the term “external stimulus” I mean here without distinction
every outward agency of nature, as well as every agency which has
its seat within the organism. The word “external” applies here to
everything with the single exception of the nervous system itself.

[30] One may be permitted to use this expression for the sake of
brevity.

[31] _Kwas_ is a favourite Russian drink, prepared from water, bread
or meal, with malt and yeast. It contains a considerable quantity of
lactic acid, some acetic acid, and other products of fermentation.

[32] An investigation by Cannon and Day (_American Journal of
Physiology_, 1903) has confirmed this conclusion. An hour after starchy
food mixed with saliva was ingested a unit volume of the food in the
cardiac end of the stomach contained almost twice the amount of sugar
found in a unit volume of the food in the pyloric end.

[33] The results of this investigation were reported to the Boston
Society of Medical Sciences, November 19, 1901.

[34] Without the possibility of seeing the relations of a movement to
the ends of the intestine, it cannot be stated absolutely whether the
movement is peristaltic or antiperistaltic. Such relations can be seen
on the fluorescent screen only near the stomach and near the ileocæcal
valve. The evidence that advancing peristalsis is the normal movement
is so overwhelming that I have assumed that when food is moving in
loops not visibly related to fixed points it is moving forward.

[35] In this case the fæces were soft.

[36] While Napoleon was building his power and fame he was very
careful and abstemious, but in later life succumbed to luxury and
gluttony; Bismarck’s rise and decline were similarly related to dietary
influences.--H. F.

*** End of this LibraryBlog Digital Book "The A.B.-Z. of our own nutrition" ***

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