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Title: Freie wissenschaft und freie lehr. English - Freedom in Science and Teaching. - from the German of Ernst Haeckel
Author: Haeckel, Ernst Heinrich Philipp August, 1834-1919
Language: English
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Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

*** Start of this Doctrine Publishing Corporation Digital Book "Freie wissenschaft und freie lehr. English - Freedom in Science and Teaching. - from the German of Ernst Haeckel" ***

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  By T. H. HUXLEY, F.R.S.

  "Welche Verehrung verdient der Weltenschöpfer der gnädig.
  Als er den Korkbaum schuf, gleich auch die Stöpfel erfand."

  549 AND 551 BROADWAY.


In complying with the wish of the publishers of Professor Haeckel's
reply to Professor Virchow, that I should furnish a prefatory note
expressing my own opinion in respect of the subject-matter of the
controversy, Gay's homely lines, prophetic of the fate of those "who
in quarrels interpose," emerge from some brain-cupboard in which they
have been hidden since my childish days. In fact, the hard-hitting
with which both the attack and the defence abound, makes me think with
a shudder upon the probable sufferings of the unhappy man whose
intervention should lead two such gladiators to turn their weapons
from one another upon him. In my youth, I once attempted to stop a
street fight, and I have never forgotten the brief but impressive
lesson on the value of the policy of non-intervention which I then

But there is, happily, no need for me to place myself in a position
which, besides being fraught with danger, would savour of presumption:
Careful study of both the attack and the reply leaves me without the
inclination to become either a partisan or a peacemaker: not a
partisan, for there is a great deal with which I fully agree said on
both sides; not a peacemaker, because I think it is highly desirable
that the important questions which underlie the discussion, apart from
the more personal phases of the dispute, should be thoroughly
discussed. And if it were possible to have controversy without
bitterness in human affairs, I should be disposed, for the general
good, to use to both of the eminent antagonists the famous phrase of a
late President of the French Chamber--"_Tape dessus._"

No profound acquaintance with the history of science is needed to
produce the conviction, that the advancement of natural knowledge has
been effected by the successive or concurrent efforts of men, whose
minds are characterised by tendencies so opposite that they are forced
into conflict with one another. The one intellect is imaginative and
synthetic; its chief aim is to arrive at a broad and coherent
conception of the relations of phenomena; the other is positive,
critical, analytic, and sets the highest value upon the exact
determination and statement of the phenomena themselves.

If the man of the critical school takes the pithy aphorism "Melius
autem est naturam secare quam abstrahere"[1] for his motto, the
champion of free speculation may retort with another from the same
hand, "Citius enim emergit veritas e falsitate quam e confusione;"[2]
and each may adduce abundant historical proof that his method has
contributed as much to the progress of knowledge as that of his rival.
Every science has been largely indebted to bold, nay, even to wild
hypotheses, for the power of ordering and grasping the endless details
of natural fact which they confer; for the moral stimulus which arises
out of the desire to confirm or to confute them; and last, but not
least, for the suggestion of paths of fruitful inquiry, which, without
them, would never have been followed. From the days of Columbus and
Kepler to those of Oken, Lamarck, and Boucher de Perthes, Saul, who,
seeking his father's asses, found a kingdom, is the prototype of many
a renowned discoverer who has lighted upon verities while following
illusions, which, had they deluded lesser men, might possibly have
been considered more or less asinine.

On the other hand, there is no branch of science which does not owe at
least an equal obligation to those cool heads, which are not to be
seduced into the acceptance of symmetrical formulæ and bold
generalisations for solid truths because of their brilliancy and
grandeur; to the men who cannot overlook those small exceptions and
insignificant residual phenomena which, when tracked to their causes,
are so often the death of brilliant hypotheses; to the men, finally,
who, by demonstrating the limits to human knowledge which are set by
the very conditions of thought, have warned mankind against fruitless
efforts to overstep those limits.

Neither of the eminent men of science, whose opinions are at present
under consideration, can be said to be a one-sided representative
either of the synthetic or of the analytic school. Haeckel, no less
than Virchow, is distinguished by the number, variety, and laborious
accuracy of his contributions to positive knowledge; while Virchow, no
less than Haeckel, has dealt in wide generalisations, and, until the
obscurantists thought they could turn his recent utterances to
account, no one was better abused by them as a typical free-thinker
and materialist. But, as happened to the two women grinding at the
same mill, one has been taken and the other left. Since the
publication of his famous oration, Virchow has been received into the
bosom of orthodoxy and respectability, while Haeckel remains an

To those who pay attention to the actual facts of the case, this is a
very surprising event; and I confess that nothing has ever perplexed
me more than the reception which Professor Virchow's oration has met
with, in his own and in this country; for it owes that reception, not
to the undoubted literary and scientific merits which it possesses,
but to an imputed righteousness for which, so far as I can discern, it
offers no foundation. It is supposed to be a recantation; I can find
no word in it which, if strictly construed, is inconsistent with the
most extreme of those opinions which are commonly attributed to its
author. It is supposed to be a deadly blow to the doctrine of
evolution; but, though I certainly hold by that doctrine with some
tenacity, I am able, _ex animo_, to subscribe to every important
general proposition which its author lays down.

In commencing his address, Virchow adverts to the complete freedom of
investigation and publication in regard to scientific questions which
obtains in Germany; he points out the obligation which lies upon men
of science, even if for no better reason than the maintenance of this
state of things, to exhibit a due sense of the responsibility which
attaches to their speaking and writing, and he dwells on the necessity
of drawing a clear line of demarcation between those propositions
which they have a fair right to regard as established truths, and
those which they know to be only more or less well-founded
speculations. Is any one prepared to deny that this is the first great
commandment of the ethics of teaching? Would any responsible
scientific teacher like to admit that he had not done his best to
separate facts from hypotheses in the minds of his hearers; and that
he had not made it his chief business to enable those whom he
instructs to judge the latter by their knowledge of the former?

More particularly does this obligation weigh upon those who address
the general public. It is indubitable, as Professor Virchow observes,
that "he who speaks to, or writes for, the public is doubly bound to
test the objective truth of that which he says." There is a sect of
scientific pharisees who thank God that they are not as those
publicans who address the public. If this sect includes anybody who
has attempted the business without failing in it, I suspect that he
must have given up keeping a conscience. For assuredly if a man of
science, addressing the public, bethinks him, as he ought to do, that
the obligation to be accurate--to say no more than he has warranty
for, without clearly marking off so much as is hypothetical--is far
heavier than if he were dealing with experts, he will find his task a
very admirable mental exercise. For my own part, I am inclined to
doubt whether there is any method of self-discipline better calculated
to clear up one's own ideas about a difficult subject, than that which
arises out of the effort to put them forth, with fulness and
precision, in language which all the world can understand. Sheridan
is said to have replied to some one who remarked on the easy flow of
his style, "Easy reading, sir, is--hard writing;" and any one who is
above the level of a scientific charlatan will know that easy speaking
is "----hard thinking."

Again, when Professor Virchow enlarges on the extreme incompleteness
of every man's knowledge beyond those provinces which he has made
his own (and he might well have added within these also), and when
he dilates on the inexpediency, in the interests of science, of
putting forth as ascertained truths propositions which the progress
of knowledge soon upsets--who will be disposed to gainsay him? Nor
have I, for one, anything but cordial assent to give to his
declaration, that the modern development of science is essentially
due to the constant encroachment of experiment and observation on
the domain of hypothetical dogma; and that the most difficult, as
well as the most important, object of every honest worker is "_sich
ent-subjectiviren_"--to get rid of his preconceived notions, and to
keep his hypotheses well in hand, as the good servants and bad masters
that they are.

I do not think I have omitted any one of Professor Virchow's main
theses in this brief enumeration. I do not find that they are disputed
by Haeckel, and I should be profoundly astonished if they were. What,
then, is all the coil about, if we leave aside various irritating
sarcasms, which need not concern peaceable Englishmen? Certainly about
nothing that touches the present main issues of scientific thought.
The "plastidule-soul" and the potentialities of carbon may be sound
scientific conceptions, or they may be the reverse, but they are no
necessary part of the doctrine of evolution, and I leave their defence
to Professor Haeckel.

On the question of equivocal generation, I have been compelled, more
conspicuously and frequently than I could wish, during the last ten
years, to enunciate exactly the same views as those put forward by
Professor Virchow; so that, to my mind, at any rate, the denial that
any such process has as yet been proved to take place in the existing
state of nature, as little affects the general doctrine.[3]

With respect to another side issue, raised by Professor Virchow, he
appears to me to be entirely in the wrong. He is careful to say that
he has no unwillingness to accept the descent of man from some lower
form of vertebrate life; but, reminding us of the special attention
which, of late years, he has given to anthropology, he affirms that
such evidence as exists is not only insufficient to support that
hypothesis, but is contrary to it. "Every positive progress which we
have made in the region of prehistoric anthropology has removed us
further from the demonstration of this relation."

Well, I also have studied anthropological questions in my time; and I
feel bound to remark, that this assertion of Professor Virchow's
appears to me to be a typical example of the kind of incautious
over-statement which he so justly reprehends.

For, unless I greatly err, all the real knowledge which we possess of
the fossil remains of man goes no farther back than the Quaternary
epoch; and the most that can be asserted on Professor Virchow's side
respecting these remains is, that none of them present us with more
marked pithecoid characters than such as are to be found among the
existing races of mankind.[4] But, if this be so, then the only just
conclusion to be drawn from the evidence as it stands is, that the men
of the Quaternary epoch may have proceeded from a lower type of
humanity, though their remains hitherto discovered show no definite
approach towards that type. The evidence is not inconsistent with the
doctrine of evolution, though it does not help it. If Professor
Virchow had paid as much attention to comparative anatomy and
palæontology as he has to anthropology, he would, I doubt not, be
aware that the equine quadrupeds of the Quaternary period do not
differ from existing _Equidæ_ in any more important respect than these
last differ from one another; and he would know that it is,
nevertheless, a well-established fact that, in the course of the
Tertiary period, the equine quadrupeds have undergone a series of
changes exactly such as the doctrine of evolution requires. Hence
sound analogical reasoning justifies the expectation that, when we
obtain the remains of Pliocene, Miocene, and Eocene _Anthropidæ_, they
will present us with the like series of gradations, notwithstanding
the fact, if it be a fact, that the Quaternary men, like the
Quaternary horses, differ in no essential respect from those which now

I believe that the state of our knowledge on this question is still
justly summed up in words written some seventeen years ago:--

"In conclusion, I may say, that the fossil remains of man hitherto
discovered do not seem to me to take us appreciably nearer to that
lower pithecoid form by the modification of which he has probably
become what he is. And considering what is now known of the most
ancient races of men; seeing that they fashioned flint axes, and flint
knives, and bone skewers of much the same pattern as those fabricated
by the lowest savages at the present day, and that we have every
reason to believe the habits and modes of living of such people to
have remained the same from the time of the mammoth and the tichorhine
rhinoceros till now, I do not know that the result is other than might
be expected."[5]

I have seen no reason to change the opinion here expressed, and so far
from the fact being in the slightest degree opposed to a belief in the
evolution of man, all that has been learned of late years respecting
the relation of the Recent and Quaternary to the Tertiary mammalia
appears to me to be in striking harmony with what we know respecting
Quaternary man, supposing man to have followed the general law of

The only other collateral question of importance raised by Professor
Virchow is, whether the doctrine of evolution should be generally
taught in schools or not. Now I cannot find that Professor Virchow
anywhere distinctly repudiates the doctrine; all that he distinctly
says is that it is not proven, and that things which are not proven
should not be authoritatively instilled into the minds of young

If Professor Virchow will agree to make this excellent rule absolute,
and applicable to all subjects that are taught in schools, I should be
disposed heartily to concur with him.

But what will his orthodox allies say to this? If "not provenness" is
susceptible of the comparative degree, by what factor must we multiply
the imperfection of the evidence for evolution in order to express
that of the evidence for special creation; or to what fraction must
the value of the evidence in favour of the uninterrupted succession of
life be reduced in order to express that in support of the deluge?
Nay, surely even Professor Virchow's "dearest foes," the "plastidule
soul" and "Carbon & Co.," have more to say for themselves, than the
linguistic accomplishments of Balaam's ass and the obedience of the
sun and moon to the commander of a horde of bloodthirsty Hebrews! But
the high principles of which Professor Virchow is so admirable an
exponent do not admit of the application of two weights and two
measures in education; and it is surely to be regretted that a man of
science of great eminence should advocate the stern bridling of that
teaching which, at any rate, never outrages common sense, nor refuses
to submit to criticism, while he has no whisper of remonstrance to
offer to the authoritative propagation of the preposterous fables by
which the minds of children are dazed and their sense of truth and
falsehood perverted. Professor Virchow solemnly warns us against the
danger of attempting to displace the Church by the religion of
evolution. What this last confession of faith may be I do not know,
but it must be bad indeed if it inculcates more falsities than are at
present foisted upon the young in the name of the Church.

I make these remarks simply in the interests of fair play. Far be it
from me to suggest that it is desirable that the inculcation of the
doctrine of evolution should be made a prominent feature of general
education. I agree with Professor Virchow so far, but for very
different reasons. It is not that I think the evidence of that
doctrine insufficient, but that I doubt whether it is the business of
a teacher to plunge the young mind into difficult problems concerning
the origin of the existing condition of things. I am disposed to think
that the brief period of school-life would be better spent in
obtaining an acquaintance with nature, as it is; in fact, in laying a
firm foundation for the further knowledge Which is needed for the
critical examination of the dogmas, whether scientific or
anti-scientific, which are presented to the adult mind. At present,
education proceeds in the reverse way; the teacher makes the most
confident assertions on precisely those subjects of which he knows
least; while the habit of weighing evidence is discouraged, and the
means of forming a sound judgment are carefully withheld from the

       *       *       *       *       *

Professor Virchow is known to me only as he is known to the world in
general--by his high and well-earned scientific reputation. With
Professor Haeckel, on the other hand, I have the good fortune to be on
terms of personal friendship. But in making the preceding
observations, I should be sorry to have it supposed that I am holding
a brief for my friend, or that I am disposed to adopt all the opinions
which he has expressed in his reply. Nevertheless, I do desire to
express my hearty sympathy with his vigorous defence of the freedom of
learning and teaching; and I think I shall have all fair-minded men
with me when I also give vent to my reprobation of the introduction of
the sinister arts of unscrupulous political warfare into scientific
controversy, manifested in the attempt to connect the doctrines he
advocates with those of a political party which is, at present, the
object of hatred and persecution in his native land. The one blot, so
far as I know, on the fair fame of Edmund Burke is his attempt to
involve Price and Priestley in the furious hatred of the English
masses against the authors and favourers of the revolution of 1789.
Burke, however, was too great a man to be absurd, even in his errors;
and it is not upon record that he asked uninformed persons to consider
what might be the effect of such an innovation as the discovery of
oxygen on the minds of members of the Jacobin Club.

Professor Virchow is a politician--maybe a German Burke, for anything
that I know to the contrary; at any rate, he knows the political value
of words; and, as a man of science, he is devoid of the excuses that
might be made for Burke. Nevertheless, he gravely charges his hearers
to "imagine what shape the theory of descent takes in the head of a

I have tried to comply with this request, but I have utterly failed to
call up the dread image; I suppose because I do not sufficiently
sympathise with Socialists. All the greater is my regret that
Professor Virchow did not himself unfold the links of the hidden bonds
which unite evolution with revolution, and bind together the community
of descent with the community of goods.

Professor Virchow is, I doubt not, an accomplished English scholar.
Let me commend the "Rejected Addresses" to his attention. For since
the brothers Smith sang--

  "Who makes the quartern loaf and Luddites rise,"--
  Who fills the butchers' shops with large blue flies,

there has been nothing in literature at all comparable to the attempt
to frighten sober people by the suggestion that evolutionary
speculations generate revolutionary schemes in Socialist brains. But
then the authors of the "Rejected Addresses" were joking, while
Professor Virchow is in grim earnest; and that makes a great
difference in the moral aspect of the two achievements.


[1] Novum Organon, li.

[2] Partis instaurationis secundæ delineatio.

[3] I may remark parenthetically that Professor Virchow's statement of
the attitude of Harvey towards equivocal generation is strangely
misleading. For Harvey, as every student of his works knows, believed in
equivocal generation; and, in the sense in which he uses the word ovum,
"nempe substantiam quandam corpoream vitam habentem potentia," the truth
of the axiom "omne vivum ex ovo," popularly ascribed to him, has in no
wise been affected by the discoveries of later days in the manner
asserted by Professor Virchow.

[4] I do not admit that so much can be said; for the like of the
Neanderthal skull has yet to be produced from among the crania of
existing men.

[5] Man's Place in Nature, p. 159.


When the address delivered by Rudolph Virchow on the 22d of September
last year, at the fiftieth meeting of German Naturalists and
Physicians at Munich, on "Freedom of Science in the Modern State,"
appeared in print in the following October, I was called upon, on many
sides, to prepare a reply. And such a reply on my part seemed, in
fact, justified by the severe strictures which Virchow in his
discourse had directed against one delivered by me only four days
previously, before the same meeting, on "The Modern Doctrine of
Evolution in its Relation to General Science." The general views which
Virchow then unfolded proved such a fundamental opposition in our
principles, and touched our dearest moral convictions so nearly, that
any reconciliation of such antagonistic views was no longer to be
thought of. Nevertheless I forbore publishing the ready reply for two
reasons: one relating to the matter itself, the other a personal one.

With regard to the matter itself, I believed I might confidently leave
it to futurity to decide in the contention that has declared itself
between us. For on one hand the doctrine of evolution which Virchow
attacks has already so far become a sure basis of biological science
and part of the most precious mental-stock of cultivated humanity,
that neither the anathemas of the Church nor the contradiction of the
greatest scientific authority--and such an one is Virchow--can prevail
against it; and on the other hand most of the arguments which he
specially adduces against the theory of descent have been so often
discussed and so thoroughly refuted that any renewed discussion seems
in fact superfluous.

Personally, it was in the highest degree repugnant to me to come
forward as the opponent of a man whom I learned, a quarter of a
century ago, to acknowledge and to honour as the reformer of medical
science; a man whose most ardent disciple and most enthusiastic
follower I at that time was, with whom I subsequently stood in the
closest relation as his assistant, and with whom I long after
continued in the most friendly intercourse. The more keenly I lamented
Virchow's position, for some years past, as the antagonist of our
modern doctrine of evolution, and the more I felt myself challenged to
a reply by his repeated attacks upon it, the less inclination I felt,
nevertheless, to come forward publicly as the opponent of this
distinguished and highly-honoured man.

And if I find myself, after all, forced to reply, it is in the
persuasion that a longer silence will add to the erroneous conclusions
which my hitherto resigned attitude has already given rise to; at the
same time I believe that, precisely by reason of the peculiar interest
with which I have throughout followed Virchow's scientific
achievements, I am specially qualified to answer the question, a
hundred times repeated by letter or by word of mouth--"How is it
possible that a man who so long stood at the head of a party of
progress in science as in politics, who in political life indeed, has
outwardly maintained this position, has in science become an
instrument of the most perilous reaction?"

A verbal answer, which I incidentally gave in March of last year at
the Concordia Banquet at Vienna, was reported in the daily papers in
such a different sense, and was in part so misunderstood or so
intentionally misrepresented, that I am forced at last, on that
account, to publish a clear and unambiguous reply. The "Augsburger
Allgemeine Zeitung," which eagerly seizes every opportunity of
expressing its unconquerable aversion to the evolution theory, accused
me, in one of its hostile articles, of a virulent and undignified
attack on Virchow. In contradiction of this misrepresentation in the
Augsburg paper--which was copied by other journals--I must expressly
assert that not Virchow but I myself am the person attacked, and
that, therefore, the matter in question is not an unjustifiable attack
by me on a formerly revered friend, but a defence to which I am
compelled by repeated and sharp attacks on his part.

Another reason which urges me at last to break silence consists in the
continual and ample advantage that all the clerical and reactionary
organs have been taking of Virchow's address, during the last
three-quarters of a year, in favour of mental retrogression. The
shouts of triumph with which they at once hailed Virchow's "grand
moral action," that is to say, his perversion from a Free-thinker to
the side of mental darkness, was the first signal for that persistent
utilisation of his authority of which the pernicious consequences can
by no means be escaped. Friedrich von Hellwald, in his discussion on
the speeches made at Munich, has already strikingly pointed out[6] the
grave danger that exists when just such an one as Virchow, standing
under the banner of political liberalism and wrapped in the mantle of
severe science, decisively combats against the freedom of science and
of its doctrines. This serious danger has never shown so threatening
an aspect as at the present moment, when our political and religious
life appears to be encountering such a reaction as has not occurred
for a long time. The two insane attempts which, within a few weeks,
have been made by Social-democracy against the revered and reverend
person of the German Emperor have raised a storm of righteous
indignation of such violence that calm judgment is entirely
overthrown, and that many even of the most liberal of liberal
politicians not only impetuously urge us to the severest measures
against the Utopian doctrines of social democracy but, far
over-shooting the mark, demand that free-doctrine and free-thought,
that freedom of the press and even freedom of conscience shall be
thrown into the narrowest fetters. Can this reaction, lurking in the
background, find any more welcome support than is afforded by the mere
demand of such a man as Virchow for restriction of liberty in
teaching? And if he makes our present doctrines of evolution in
general and the theory of descent in particular responsible for the
mad doctrines of social-democracy, it is but a natural and just
consequence when the famous New-Prussian "Kreuz-Zeitung" throws all
the blame of these treasonable attempts of the democrats Hödel and
Nobiling--as in fact it quite lately did--directly on the theory of
descent, and especially on the hated doctrine of the "descent of man
from apes." And the danger which threatens us shows a still graver
aspect when we consider how great an influence Virchow has at the
present day as an advanced liberal, and how he is regarded in the
Prussian diet as the highest practical authority, and at the same time
as the most liberal critic when educational questions are under
consideration. Now it is well known that one of the most important
problems lying before the Prussian parliament is the consideration of
a new education-law, which will probably exercise its restricting
influence for a long time to come, not in Prussia only, but throughout
Germany; what can we expect of such an education-law if in the course
of the deliberations, among the small number of those specialists who
are generally listened to, Virchow raises his voice as a leading
authority, and brings forward the principles that he proclaimed in his
speech at Munich as the surest guarantees for the freedom of science
in the modern polity? Article XX. of the Prussian Charter, and § 152
of the Code of the German Empire, say, "Science and its doctrines are
free." And Virchow's first step, according to the principles he now
declares, must be a motion to abrogate this paragraph.

In the face of this imminent danger, I dare no longer hesitate about
my answer. _Amicus Socrates, amicus Plato, magis amica Veritas._ An
unreserved and public opposition can be no longer postponed. As a
matter of fact, at the Munich meeting, neither did Virchow hear my
speech nor I his. I read my paper, as it is printed, on the 18th
September 1877, and left on the 19th. Virchow came to Munich only on
the 20th, and delivered his speech on the 22d.

Bearing in mind the gratitude which I owe to Virchow as my former
master and friend at Würzburg--a gratitude which I have at all times
striven to prove by the further development of his mechanical
theory--I shall confine myself, as far as possible, to an objective
and special confutation of his assertions. Certainly the temptation on
this occasion was a strong one to pay the debt in like kind. In my
Munich lecture, among the few names to which I alluded, I particularly
mentioned that of Virchow as the distinguished founder of
cellular-pathology (p. 12).[7] Virchow's return for this was to heap
scorn and ridicule on the doctrine of evolution in his usual manner.
The critic in the "National-Zeitung," Herr Isidor Kastan, says of this
with particular satisfaction, "The ridicule with which Herr Virchow
treated this side of Haeckel's visions was indeed caustic enough, but
this is ever Virchow's way; only in this case, if in any, he was fully

I could less easily ignore Virchow's denunciation of me than his
satire--a denunciation which gibbeted me as a confederate in the
social-democratic cause, and which made the theory of descent
answerable for the horrors of the Paris Commune. The opinion is now
widely spread that by this intentional connection of the theory of
descent with Social Democracy he has hit the hardest blow at that
theory, and that he aimed at nothing less than the removal of all
"Darwinists" from their academic chairs and professorships. This is
the inevitable consequence of his demands; for if Virchow insists with
the utmost determination that the theory of descent must not be taught
(because he does not regard it as true), what is to become of the
supporters of that theory who, like myself, regard it as
incontrovertibly true, and teach it as a perfectly sound theory? And
at least nine-tenths of all the teachers of zoology and botany in
Europe are among its supporters from immutable conviction of its
truth, as well as all morphologists without exception. Virchow cannot
expect that these teachers should collectively renounce that which
they believe to be immutable truth, and in its place set up the dogma
of the Church as the basis of their teaching, in accordance with his
wish! Nothing remains for them but to vacate their professors' chairs,
and--according to Virchow and the "Germania"--the "Modern Polity"
would be in duty bound to deprive them of their liberty of teaching if
they did not voluntarily renounce it.

If this be indeed Virchow's purpose, as it is generally supposed to
be, with regard to me, at least, he may spare himself the trouble.
Amongst us in Jena quite other ideas prevail as to the "Freedom of
science in the modern Polity" than those which obtain in the capital,
Berlin. And among us the Berlin students' rhyme has no meaning,

  "Who knows the truth and freely speaks,
  On him the law its vengeance wreaks."[8]

The Jena students, on the contrary, sing the rhyme in its original

  "Who knows the truth and speaks it not,
  A feeble wretch is he, God wot."[9]

The Rector Magnificentissimus of the University of Jena, the Grand
Duke of Saxony, who has proved himself the protector of the arts and
sciences, has besides far more liberal views as to the liberty of
scientific investigation and teaching than the illustrious head of the
party of progress at Berlin. The enlightened and liberal Prince at
Weimar, under whose particular protection we in Jena find ourselves,
has never conceived it necessary to limit in any way the unbounded
freedom of my teaching and my writing; not even when in 1866 my
"General Morphology," and 1868 my "History of Creation" first
appeared, and when many people attempted to make the youthful
extravagances which were to be found in those works the ground of a
serious accusation. And what farther mischief have these extravagances
done, though I now sincerely lament them?

Faithful to the glorious traditions of a past extending over three
centuries, the little Thuringian university of Jena will find a way to
preserve her perfect and unlimited freedom. She will ever bear in mind
that she is the first Protestant university of Germany, protesting
against every strait-waistcoat which hierarchical obstinacy would
force upon human reason, against every dogma by which the arrogance of
the learned may try to suppress all freedom of teaching. She will
freely seek and freely teach in accordance with her highest
convictions, untroubled by the fact that in the "great" university of
Berlin nothing may be taught, as Virchow insists, but what is
objectively ascertained, absolutely sure; that is to say, nothing that
rises above individual, indubitable, and intelligible facts; not an
idea, not a conception, not a theory, in fact not any real science;
mathematics, at most, excepted. It is our conviction that Jena will
continue to be an independent city of refuge for free science and free
teaching as long as it remains under the faithful nurture and liberal
protection of the princely house of Sax Weimar, that enlightened race
which is linked with the history of German intellect through the
matchless traditions of its glorious past. What the Wartburg was to
Martin Luther, what Weimar has been to the foremost heroes of German
literature, what Jena herself has been during three hundred years to a
vast number of illustrious investigators, that will the tried and
tested Jena of to-day undoubtedly continue to be to the modern
doctrine of evolution, as to every other doctrine which asks free
development; a strong-hold of free thought, free investigation, and
free doctrine.


JENA, _June 24th_, 1878.


[6] Kosmos, Vol. II. p. 172.

[7] Of the German.


  "Wer die Wahrheit kennet und saget sie frei,
   Der kommt in Berlin auf die Stadt-Vogtei."


  "Wer die Wahrheit kennet und saget sie nicht
  Der ist für wahr ein erbärmlicher Wicht."



       PREFATORY NOTE                                            v

       PREFACE                                                 xxi


    I. DEVELOPMENT AND CREATION                             1






  VII. IGNORABIMUS ET RESTRINGAMUR                         99




Nothing is more helpful for the understanding of scientific
controversies, or for the clearing of confused conceptions, than a
contrasted statement, as defined and clear as possible, of the
simplest leading propositions of the contending doctrines. Hence it is
highly favourable to the victory of our modern doctrine of evolution
that its chief problem, the question as to the origin of species, is
being more and more pressed by these opposite alternatives: Either all
organisms are naturally evolved, and must in that case be all
descended from the simplest common parent-forms--or: That is not the
case, and the distinct species of organisms have originated
independently of each other, and in that case can only have been
created in a supernatural way, by a miracle. Natural evolution, or
supernatural creation of species--we must choose one of these two
possibilities, for a third there is not.

But as Virchow, like many other opponents of the doctrine of
evolution, constantly confounds this latter proposition with the
doctrine of descent, and that again with Darwinism, it will not be
superfluous to indicate here, in a few words, the limitation and
subordination of these three great theories.

I. The general doctrine of development, the progenesis-theory or
evolution-hypothesis (in the widest sense), as a comprehensive
philosophical view of the universe, assumes that a vast, uniform,
uninterrupted and eternal process of development obtains throughout
all nature; and that all natural phenomena without exception, from the
motions of the heavenly bodies and the fall of a rolling stone to the
growth of plants and the consciousness of men, obey one and the same
great law of causation; that all may be ultimately referred to the
mechanics of atoms--the mechanical or mechanistic, homogeneous or
monistic view of the universe; in one word, Monism.

II. The doctrine of derivation, or theory of descent, as a
comprehensive theory of the natural origin of all organisms, assumes
that all compound organisms are derived from simple ones, all
many-celled animals and plants from single-celled ones, and these last
from quite simple primary organisms--from monads. As we see the
organic species, the multiform varieties of animals and plants, vary
under our eyes through adaptation, while the similarity of their
internal structure is reasonably explicable only by inheritance from
common parent-forms, we are forced to assume common parent-forms for
at least the great main divisions of the animal and vegetable
kingdoms, and for the classes, orders, and so forth. Thus the number
of these will be very limited, and the primitive archigonian
parent-forms can be nothing else than monads. Whether we finally
assume a single common parent-form (the monophyletic hypothesis), or
several (the polyphyletic hypothesis), is wholly immaterial to the
essence of the theory of descent; and it is equally immaterial to its
fundamental idea what mechanical causes are assumed for the
transformation of the varieties. This assumption of a transformation
or metamorphosis of species is, however, indispensable, and the theory
of descent is very properly called also the "metamorphosis
hypothesis," or "doctrine of transmutation;" as well as Lamarckism,
after Jean Lamarck, who first founded it in 1809.

III. The doctrine of elimination, or the selection theory, as the
doctrine especially of "choice of breed or selection," assumes that
almost all, or at any rate most, organic species have originated by a
process of selection; the artificial varieties under conditions of
domestication--as the races of domestic animals and cultivated
plants--through artificial choice of breeds; and the natural varieties
of animals and plants in their wild state by natural choice of breeds:
in the first case, the will of man effects the selection to suit a
purpose; in the second, it is effected in a purposeless way by the
"struggle for existence." In both cases the transformation of the
organic forms takes place through the reciprocal action of the laws of
inheritance and of adaptation; in both cases it depends on the
survival or selection of the better-qualified minority. This theory of
elimination was first clearly recognised and appreciated in its full
significance by Charles Darwin in 1859, and the selection-hypothesis
which he founded on it is Darwinism properly so called.

The relation that these three great theories, which are frequently
confounded, bear to one another may, according to the present position
of science, be simply defined as follows:--I. Monism, the universal
theory of development, or the monistic progenesis-hypothesis, is the
one only scientific theory which affords a rational interpretation of
the whole universe and satisfies the craving of our human reason for
causality, by bringing all natural phenomena into a mechanical
causal-connection as parts of a great uniform process of evolution.
II. The theory of transmutation, or descent, is an essential and
indispensable element in the monistic development hypothesis, because
it is the one only scientific theory which rationally explains the
origin of organic species--that is to say, by transformation--and
reduces it to mechanical principles. III. The theory of Selection or
Darwinism is, up to the present time, the most important of the
various theories which seek to explain the transformation of species
by mechanical principles, but it is by no means the only one. If we
assume that most species have originated through natural elimination,
we also now know, on the other hand, that many forms distinguished as
varieties are hybrids between two different varieties, and can be
propagated as such; and it is equally well worthy of consideration
that other causes are in activity in the formation of species of
which, up to the present time, we have no conception. Thus it is left
to the judgment of individual naturalists to decide what share is to
be attributed to natural selection in the origin of species, and even
at the present day authorities differ widely on the subject. Some give
it a large share, and some a very small one in the result. Moritz
Wagner, for instance, would substitute his own migration-hypothesis
for Darwin's theory of selection; while I regard the action of
migration, which acts as isolation or separation, as merely a special
mode of selection. But these differing estimates of Darwinism are
quite independent of the absolute import of the doctrine of descent
or of transformation, for the latter is as yet the only theory which
rationally explains the origin of species. If we discard it, nothing
remains but the irrational assumption of a miracle, a supernatural

In this crucial and unavoidable dilemma, Virchow has declared himself
publicly in favour of the latter, and against the former hypothesis.
Every one who has attentively followed his occasional utterances on
the theory of descent during the last decade with an unprejudiced eye
and an unbiassed judgment, must be convinced that he fundamentally
rejects it. Still, his dissent has always been so obscured, and his
judgment on Darwinism in particular so wrapped in ambiguities, that an
opportune conversion to the opposite side seemed not impossible; and
many, even among those who stood near to Virchow--his friends and
disciples--did not know to what point he was in fact an opponent of
the evolution hypothesis in general. Virchow took the last step
towards clearing up this matter at Munich; for after his Munich
address there can be no farther doubt that he belongs to the most
decided opponents of the whole theory of evolution, including those of
inheritance and selection.

If any one still has doubts on the matter, let him read the jubilant
hymns of triumph with which Virchow's friend and collaborator, Adolf
Bastian, greeted his Munich discourse. This "enfant terrible" of the
school--this well-nicknamed "Acting privy counsellor of the board of
confusion"[10]--whose merits in involuntarily advancing the cause of
metamorphism I have already done justice to in the preface to the
third edition of my "Natural History of Creation"[11]--expresses
himself in the "Zeitschrift für Ethnologie," which is edited by him
and Virchow (tenth yearly part, X. 1878, p. 66) as follows:--"At the
Munich meeting of naturalists, Virchow by a few weighty words cleared
the atmosphere, which was heavy and stifling under the pressure of the
incubus called Descent, and once more freed science from that
nightmare which it has so long--in many opinions so much too
long--allowed to weigh upon it; freed it, let us hope, once and for
ever. The forecasts of this storm were discernible many years since,
and its whole course has been a strictly normal one. When the germs
planted by Darwin, and that promised so much, were forced into growth
by a feverish, hot-house heat, and began to sprout into sterile weeds,
their small vitality was plain to our eyes. So long as the waves run
too high under the pressure of a psychical storm, it is almost useless
to protest against it, for every ear is too much deafened by the
noise all round to hear the voice of individuals. It is best to leave
things to go their own way, deeper and deeper into the mire, till they
come to a stand-still there of their own accord; for 'Quos deus vult
perdere prius dementat.' Thus it is in this case. When the
extravagances of the descent hypothesis, encouraged as they were by
mutual incitement, had reached their highest pitch in the ravings that
were uttered at Munich, the too pointed point broke in this
superabundance of absurdity almost by its own pointedness, and so we
were quit of it with one blow. Now, happily, all is over with the
theory of descent, or ascent, but natural science will not on that
account fare any the worse, for many of its adherents belong to her
ablest youth, and as they now need no longer waste their best time on
romantic schemes, they will have it to use at the orders and for the
advancement of science, so as to enrich her through real and solid

Furthermore, Bastian quotes Virchow's maxim:--"The plan of
organisation is immutable within the limits of the species; species is
not produced from species." The fundamental teleological idea of that
school, that each species has its constant and specific plan of
structure, certainly cannot be more emphatically expressed. Thus it is
undoubtedly certain that Virchow has become a Dualist, and is as
thoroughly penetrated by the truth of his principles as I, as a
Monist, am of mine. This is undoubtedly the upshot of his Munich
address, though he is throughout careful to avoid acknowledging his
chief standpoint in all its nakedness. On the contrary, even now he
still veils his antagonism under the phrase, which is also a favourite
with the clerical papers, that the theory of descent is an "unproved
hypothesis." Now it is clear that this theory never will be "proved"
if the proofs that already lie before us are not sufficient. How often
has it been repeated that the scientific certainty of the hypothesis
of descent is not grounded in this or that isolated experiment, but in
the collective sum of biological phenomena; in the causal nexus of
evolution. Then what are the new proofs of the theory of descent which
Virchow demands of us?


[10] "Wirkliche Geheime Ober-Confusionsrath."

[11] Translated under the supervision of E. Ray Lankester. London: C.
Kegan Paul & Co.



All the common phenomena of Morphology and Physiology, of Chorology
and Oekology, of Ontology and Paleontology, can be explained by the
theory of descent, and referred to simple mechanical causes. It is
precisely in this, viz., that the primary simple causes of all these
complex aggregates of phenomena are common to them all, and that other
mechanical causes for them are unthinkable--it is in this that, to us,
the guarantee of their certainty consists. For this reason all these
vast and manifold aggregates of facts are so many evidences of the
doctrine of descent. This fundamental relation of facts has been so
often expounded that I need dwell no farther on it in this place;
those who wish for any closer discussion of it are referred to my
"General Morphology" (vol. ii. chap. xix.), or "The History of
Creation,"[12] or "The Evolution of Man" (vol. i. p. 93).[13]

And where is yet farther proof of the truth of the theory of descent
to be found? Neither Virchow, nor any one of the clerical opponents
and the dualistic philosophers who are perpetually reiterating this
cry for more certain evidence, anywhere indicate where possibly such
evidence is to be sought. Where in all the world can we discover
"facts" which will speak more plainly or significantly for the truth
of transmutation than the facts of comparative morphology and
physiology; than the facts of the rudimentary organs and of embryonic
development; than the facts revealed by fossils and the geographical
distribution of organisms--in short, than the collective recognised
facts of the most diverse provinces of biological science?

But I am in error--the certain proof that Virchow demands in order to
be perfectly satisfied with the evidence, is to be supplied by
"experiment, the test as well as the highest means of evidence." This
demand, that the doctrine of descent should be grounded on experiment,
is so perverse and shows such ignorance of the very essence of our
theory, that though we have never been surprised at hearing it
continually repeated by ignorant laymen, from the lips of a Virchow it
has positively astounded us. What can in this case be proved by
experiment, and what can experiment prove?

"The variability of species, the transformation of species, the
transition of a species into one or more new varieties," is the
answer. Now, so far as these facts can be proved by experiment, they
actually have long since been experimentally proved in the completest
manner. For what are the numberless trials of artificial selection for
breeding purposes which men have practised for thousand of years in
breeding domestic animals and cultivated plants, but physiological
experiments which prove the transformation of species? As an example
we may refer to the different races of horses and pigeons. The swift
race-horse and the heavy pack-horse, the graceful carriage-horse and
the sturdy cart-horse, the huge dray-horse and the dwarfed pony--these
and many other "races" are so different from each other, that if we
had found them wild we should certainly have described them as quite
different varieties of one species, or even representatives of
different species. Undoubtedly, these so-called "races" and "sports"
of the horse tribe differ from each other in a much greater degree
than do the zebra, the quagga, the mountain horse, and the other wild
varieties of the horse, which every zoologist distinguishes as "bonæ
species." And yet all these artificial varieties, which man has
designedly produced by selection, are descended from a single common
parent-form, from one wild "true variety." The same is the case with
the numerous and highly differing varieties of pigeons. Domestic
pigeons and carrier-pigeons, turbits and cropper-pigeons, fantail
pigeons and owls, tumblers and pouters, trumpeters and laughing
pigeons (or Indian doves), and the rest, are all, as Darwin has
convincingly proved, descendants of a single wild variety, the
rock-pigeon (_Columba livia_). And how wonderfully various they are,
not only in general form, size, and colouring, but in the particular
form of the skull, the beak, the feet, and so forth! They differ much
more in every respect each from the others than the numerous wild
varieties which, in systems of ornithology, are recognised as true
varieties, and even as true species. It is the same with the different
artificial varieties of apples, pears, pansies, dahlias, and so on; in
short, of almost all the domestic varieties of animals and plants. We
would lay particular stress on the fact that these artificial species
which man has produced or created by artificial breeding and through
experimental transformation out of one original species, differ far
more one from another in physiological as well as in morphological
conditions than the natural species in a wild state. With these it is
self-evident that any proof by experiment of a common origin is wholly
impossible. For, so soon as we subject any wild variety of animal or
plant to such an experiment, we bring it under the conditions of
artificial breeding.

That the morphological conception of a Species is not a positive but
only a relative conception, and that it has no other absolute or
positive value than those other similar system-categories--sports,
varieties, races, tribes, families, classes--is now acknowledged by
every systematiser who forms an honest and unprejudiced judgment of
the practical systematic distinction of species. From the very nature
of the case there are no limits to arbitrary discretion in this
department, and there are no two systematists who are at one in every
instance; this one separating forms as true varieties which that one
does not. (Compare on this point "History of Creation," vol. i., p.
273.) The conception of variety or species has a different value in
every small or large department of systematic Zoology and Botany.

But the conception of species has just as little any fixed
physiological value. In respect to this we must especially insist that
the question of hybrid offspring, the last corner of refuge of all the
defenders of the constancy of species, has at present lost all
significance as bearing on the conception of species. For we know now,
through numerous and reliable experiences and experiments, that two
different true varieties can frequently unite and produce fertile
hybrids (as the hare and rabbit, lion and tiger, many different kinds
of the carp and trout tribes, of willows, brambles, and others); and
in the second place, the fact is equally certain that descendants of
one and the same species which, according to the dogma of the old
schools, could always effect a fertile union under certain
circumstances, either cannot effect such a union or produce only
barren hybrids (the Porto-Santo rabbit, the different races of horses,
dogs, roses, hyacinths, &c.; see "History of Creation," vol. i., p.

For a certain proof that the conception of species rests on a
subjective abstraction and has a merely relative value--like the
conception of genus, family, order, class, &c.--no class of animals is
of so much importance as that of the Sponges. In it the fluctuating
forms vary with such unexampled indefiniteness and variability as to
make all distinction of species quite illusory. Oscar Schmidt has
already pointed this out in the siliceous sponges and keratose
sponges; and I, in my monograph, in three volumes, on the Calcareous
Sponges (the result of five years of most accurate investigations of
this small animal group), have pointed out that we may at pleasure
distinguish 3, or 21, or 111, or 289, or 591 different species. I also
believe that I have thus convincingly demonstrated how all these
different forms of the calcareous sponges may quite naturally, and
without any forcing, be traced to a single common parent-form, the
simple--and not hypothetical, but existing at this present day--the
simple Olynthus. Hence I think I have here produced the most positive
analytical evidence of the transformation of species, and of the unity
of the derivation of all the species of a given group of animals, that
is generally possible.

Properly, I might spare myself these disquisitions on the question of
species, for Virchow does not go into this main question of the theory
of descent--but this is very characteristic of his attitude. And just
as he nowhere thoroughly discusses the doctrine of transformation,
neither does he enter generally on the refutation of any of the other
certain proofs of the doctrine of descent which we in fact possess at
the present day. Neither the morphological nor the physiological
arguments for the theory of descent, neither the rudimentary organs
nor the embryonic forms, neither the paleontological nor the
chronological argument are anywhere closely examined and tested as to
their worth or their worthlessness as "certain proofs." On the
contrary, Virchow takes them quite easily, sets them aside, and
declares that "certain proofs" of the doctrine of descent do not
exist, but remain to be discovered. To be sure, he does not indicate
where they are to be sought, nor can he indicate it. How is this
strange conduct to be explained? How is it possible that a
distinguished naturalist should resist the most important step forward
of modern natural science without in any way specially investigating
it, without even practically testing and refuting the most weighty
arguments in its favour? To this question there is but one answer.
Virchow is not generally intimate with the modern doctrine of
evolution, and does not possess that knowledge of natural science
which is indispensable for any well-grounded judgment on it.

After collecting and carefully reading all that Virchow, during many
years, had written against evolution, I arrived at the conviction that
he had not thoroughly read either Darwin's great work on the Origin of
Species, nor any other work on the theory of descent, nor had he
thought the matter out with such attention as so serious and intricate
a subject absolutely demands. Virchow did with these works as it has
been his well-known custom to do with many others--he hastily turned
over the pages, caught at a few leading words, and without any farther
trouble he has discoursed upon them, and, which is worst of all, has
perpetuated these discourses through the press.

To excuse this conduct, and to account for Virchow's enigmatical
position in the battle of evolution, we must consider what changes
this highly-gifted and meritorious man has gone through in the course
of the last thirty years. The most important and fruitful part of his
life and labours was indisputably during the eight years when he
resided in Würzburg, from 1848 to 1856. There Virchow, with all the
keenness of his youthful intellect, with a sacred enthusiasm for
scientific truth, with indefatigable powers of work and the rarest
insight, worked out that glorious reform of scientific medicine which
will shine through all time as a star of the first magnitude in the
history of medical science. In Würzburg, Virchow elaborated that
comprehensive application of the cellular theory to pathology which
culminates in the conception that the cell is an independent living
elementary organism, and that our human organism, like that of all the
higher animals, is merely a congeries of cells--a highly fertile
conception, which Virchow now denies as resolutely as he then
supported it. In Würzburg, twenty-five years since, I sat devoutly at
his feet, and received from him with enthusiasm that clear and simple
doctrine of the mechanics of all vital activity--a truly monistic
doctrine, which Virchow now undoubtedly opposes where formerly he
defended it. In Würzburg, finally, he wrote those incomparable
critical and historical leading articles which are the ornament of the
first ten yearly series of his "Archives" of pathological anatomy. All
that Virchow effected as the great pioneer of reform in medicine, and
by which he won imperishable honour in the scientific treatment of
disease,--all this was either carried out or preconceived in Würzburg;
and even the celebrated "Cellular Pathology," a course of lectures
which he delivered during the first year and a half after quitting
Würzburg for Berlin, consists only of the collected and matured fruits
of which the blossoms are due to Würzburg.

In the autumn of 1856 Virchow left Würzburg to settle in Berlin. The
exchange of a narrow sphere of labours for a wider one, of small means
and appliances for greater ones, proved unfavourable in this case, as
in many similar cases. Since he has been in Berlin, in a "great
Institution," and with luxurious appliances, all the scientific
results which Virchow has as yet brought to light are not to be
compared, either as to quality or quantity, to the grand and immortal
achievements which he himself effected in the little institute of
Würzburg with the scantiest means--a new proof of the maxim enunciated
by me, and hitherto never confuted, that "the scientific results of an
institute are in inverse proportion to its size." (See "The Aim and
Methods of Modern Evolution."[14])

Still more grave is the circumstance that, since settling in Berlin,
Virchow has more and more exchanged his theoretical scientific
activity for practical political life. It is well known how prominent
a part he plays there in the Prussian Chamber of Representatives, how
he raised himself to be the leader of the party of progress, and, to
give this political position a broader basis, took part in the
representation of the citizens of the capital; how he has taken a most
active interest, as city commissioner, in all the petty anxieties and
concerns which the charge of such a city as Berlin entails. I am far
from blaming, as many have blamed, the political and civic activity to
which Virchow has indefatigably devoted his best powers. If a man
feels in himself the inclination and vocation with strength and talent
enough, to play a conspicuous political part, by all means let him do
so; but verily I do not envy him; for the satisfaction which is
derived from the most successful and fruitful political activity is
not, to my taste, to be compared with that pure and disinterested
satisfaction of the mind which results from absorption in serious and
difficult scientific labours. In the turmoil of the political and
social struggle, even the most splendid civic crown will be dulled by
the stifling dust of practical life, which never reaches the ethereal
heights of pure science and never rests on the laurels of the
thoughtful investigator. However, as I have said, that is a matter of
taste. If Virchow really believes that he is doing a greater service
to humanity by his practical political life in Berlin than he
formerly did by his theoretical scientific work in Würzburg, that is
his affair; but for all that, in his former sphere he was
incomparable, and cannot be replaced; in the latter this is not the

If a distinguished man, be he never so remarkable for uncommon power
of work and universal gifts, passes the whole day in the friction of
political party-struggles, and throws himself as well into all the
petty and wearisome details of daily civic life, it is impossible for
him to maintain the requisite feeling for the progress of
science--particularly when it advances so rapidly and incessantly as
is the case in our day. It is therefore quite intelligible that
Virchow should soon have lost this feeling, and in the course of the
last two decades have become more and more estranged from science. And
this estrangement has at last led to so complete a change in his
fundamental views, to such a metapsychosis, that the present Virchow
of 1878 is hardly in a position to understand the youthful Virchow of

We have seen a similar mental change occur contemporaneously in our
greatest naturalist, Carl Ernst von Baer. This gifted and profound
thinker and biologist, whose name marks a new epoch in the history of
evolution, had in his later years become wholly incompetent even to
understand those most important problems of his youthful labours
which opened up new paths of inquiry. While in his early years he laid
down principles of the greatest value to our modern doctrine of
evolution, and even went very near to adopting this hypothesis into
his system, at a later period he utterly denied it, and by his
writings on Darwinism proved that he was no longer generally capable
of mastering this difficult problem. As I am one of Von Baer's warmest
admirers, and in my "Evolution of Man," as well as in the "History of
Creation," and in other places, have most emphatically expressed that
sincere esteem, I thought I might venture to forbear from calling
attention to the discrepancy between the lucid, monistic principles of
Von Baer in his youth, and the confused dualistic views of his old
age. But as many opponents of Darwinism--and among them particularly
the Old Catholic philosopher of Munich, Huber, who has written a
series of articles in the "Augsburger Zeitung"--have made constant
capital out of the harmless talk of the feeble old Von Baer, I must in
this place explicitly declare that this dualistic prating of the old
man is quite incapable of shaking the monistic principles of the young
and enterprising pioneers of science, or of giving them the lie.

In his autobiography Von Baer gives us the explanation of this
striking contradiction. In 1834 he entirely and for ever abandoned
the province of the history of development, at which for twenty years
he had laboured incessantly, and where he had earned splendid laurels.
To escape from the haunting and importunate ideas of the science which
had so wholly absorbed him, he fled from Königsberg to Petersburg, and
subsequently busied himself in scientific inquiries of a quite
different character. Twenty-five long years passed by, and when
Darwin's work appeared in 1859, Von Baer had too long undergone a
metapsychosis to be able to understand it. In Von Baer, as in Virchow,
the course of this remarkable metapsychosis is highly instructive, and
will itself afford to the thoughtful psychologist an interesting
evidence of the doctrine of evolution.

However, the lack of comprehension of our modern evolution-hypothesis
is easier to explain in Virchow's case than in Von Baer's, for this
reason: morphological knowledge was greatly lacking to Virchow, while
Von Baer possessed it in the highest degree. Now morphology is
precisely that very department of inquiry in which our theory of
descent has its deepest and strongest roots, and has matured the most
glorious fruits of knowledge. The study of organic forms, or
morphology, is thus, more than any other science, interested in the
doctrine of descent, because through this doctrine it first obtained a
practical knowledge of effective causes, and was able to raise itself
from the humble rank of a descriptive study of _forms_ to the high
position of an analytical science of _form_. It is true that by the
beginning of this century the most comprehensive branch of
morphology--_i.e._, comparative anatomy--which was founded by Cuvier
and splendidly developed by Johannes Müller, had laid the foundations
on which to build a truly philosophical science of form. The enormous
mass of various empirical material, which had been accumulated by
descriptive systematists and by the dissections of zootomists since
the time of Linnæus and Pallas, had already been abundantly matured
and utilised in many ways for philosophic purposes by the synthetic
principles of comparative anatomy. But even the most important
universal laws of organisation--of which the old system of comparative
anatomy was one--had to take refuge in mystical ideas of a plan of
structure and of creative final causes (_causæ finales_); they were
incapable of arriving at a true and clear perception of effective
mechanical causes (_causæ efficientes_). This last, most difficult,
and grandest problem, Charles Darwin was the first to solve in 1859,
by setting Lamarck's theory of descent, which was already fifty years
old, on a firm footing by his own theory of selection. By this
hypothesis it was first made possible to fit together the rich
materials which had been previously amassed, into the splendid
edifice of the mechanical science of form. (See my "General
Morphology," vol. i. chap. iv.)

The immeasurable step which Darwin thus made in organic morphology can
be adequately appreciated only by those who, like myself, were brought
up in the school of the old teleological morphology, and whose eyes
were suddenly opened by the theory of selection to a comprehension of
that greatest of all biological riddles, the creation of specific
forms. The dogma of creation, the mystic and dualistic doctrine of the
isolated creation of each separate variety, was annihilated at one
blow; the belief in transmutation has now for ever taken its
place--the mechanistic and monistic doctrine of the metamorphosis of
organic forms, of the descent of all the species of one natural class
from a common parent-form. How complete a change the science of
mechanical morphology has by this means been compelled to undergo, I
have endeavoured to point out in my "General Morphology;" and any one
who wishes to convince himself clearly of what an enormous revolution
has been brought about, particularly in comparative anatomy, may
compare the "Outlines of Comparative Anatomy" (Grundzüge der
vergleichenden Anatomie), by Carl Gegenbaur, 1870, and the latest
edition of his "Elements" (Grundrisses), with the old text-books of
that science.

Virchow has no suspicion even of all these immeasurable strides in
morphology, for this department always lay out of his ken. His great
reforms in pathology were founded in the province of physiology, and
more especially in cellular physiology. But within the last twenty
years these two main branches of biological inquiry have grown more
and more apart. The great Johannes Müller was the last biologist who
was able to keep these departments of organic inquiry together, and
who won equally immortal honours in both divisions of the subject.
After Müller's death in 1858 they fell asunder. Physiology, as the
science especially of the functions or living activity of the
organism, addressed itself more and more to exact and experimental
methods: morphology, on the contrary, as the science of the forms and
structure of animals and plants, could naturally make but very small
use of this method; it must take refuge more and more in the history
of evolution, and so constitute an historical natural science. It was
on this very historical and genetic method of morphology, in
contradistinction to the exact and experimental method of physiology,
that I based my Munich address; and if Virchow in his answer had
really and thoroughly refuted this position, instead of fighting with
mere phrases and denunciations, this radical opposition would have
been well worthy of the fullest discussion. At the same time I have
no wish to reproach Virchow for being wholly fettered by the one-sided
views of the modern school-physiology, nor because morphology lies so
far out of his ken that he has not been able to form an independent
judgment of its aims and methods; but when, in spite of all this, he
on every occasion lets fall a disparaging judgment of it, we must
dispute his competence. It is true that in his Munich address he
emphasises the statement, "That which graces me best is that I know my
ignorance," by printing it in italics. I only regret that I am forced
to deny his possession of this very grace. Virchow does not know how
ignorant he is of morphology, else he would never have uttered his
annihilating verdict on it, else he would not continually designate
the study of the theory of descent as dilettanteism and vain dreaming,
as "a fanciful private speculation which is now making its way in
several departments of natural science." In truth, Virchow does me
greatly too much honour when he designates as my "personal crotchet"
an idea which for the last ten years has been the most precious common
possession of all morphological science. If Virchow were not so
unfamiliar with the literature of morphology, he must have known that
it is penetrated throughout by this principle of descent, that every
morphological inquiry which conscientiously pursues a well-considered
problem now assumes the doctrine of descent as granted and
indisputable. Of all this he is ignorant, and so it is intelligible
that he should continue to demand "certain proofs" of this hypothesis,
although those proofs have long since been produced.


[12] Vol. ii., p. 334 of translation.

[13] London: C. Kegan Paul & Co. 1879.

[14] Jena, Zeitschriften für Naturwissenschaft, 1875. Vol. x.



Inasmuch as Virchow persists in treating the theory of descent as an
"unproved hypothesis," inasmuch as he ignores all the forcible
evidences of that hypothesis, he deprives himself of the right of
speaking a decisive word in this, the most important scientific
dispute of the present day. Virchow is, in fact, simply incompetent in
the great question of evolution, as he is deficient in the greater
part of that knowledge--more especially morphological knowledge--which
is indispensable to forming a judgment upon it. Hence on the
turning-point of the whole matter--viz., the problem as to the origin
of species--he can have no opinion, as he has never turned his
attention to the systematic treatment of species: those transitions of
one species into another, which he asks to see, abound on all sides,
as is well known to every systematic naturalist. Only consider, for
example, the genera of Rubus and Salix among the living plants of the
present period, and the Ammonites and Brachiopoda among extinct
animals. Hence, too, Virchow can have no independent views as to the
historical development of the higher from the lower animals, because
the abundant living forms of the lower animals are almost unknown to
him, and because he has hardly any conception of the marvellous
strides which hundreds of industrious workers have made in this very
department within the last twenty years. But there can be no doubt,
indeed it is already universally acknowledged, that it is precisely
the comparative anatomy of the lower--nay, of the very lowest
animals--that has solved the greatest riddles of life, and removed the
greatest obstacles from the path of the doctrine of descent. He simply
ignores the fact that true Monads actually exist, and have been
positively identified by many different observers as structureless
"organisms without organs," and he turns out the poor Bathybius with a
kick. And yet I believe that in "Kosmos"[15] I have conclusively proved
that Monads must retain their vast elementary importance whether the
Bathybius actually exists or not.

But even as regards the higher animals--nay, even as to the
comparative anatomy of the highest next to man, the apes--Virchow
stands apart, not understanding the views of modern morphology.

We must here examine more closely into this, because it is precisely
in this department that Virchow's only morphological experiments have
been made; viz., his investigations as to the skulls of apes and of
men. This is precisely the one only point on which he has sought a
closer acquaintance with morphology, and precisely here it is most
clearly to be seen how little he is acquainted with the recent
advances our science has made, and that he has hardly any conception
of the extraordinary importance to that science of the theory of

The skull theory, as is well known, has for a long time been a very
favourite theme, not only with prominent naturalists, but also with
talented amateurs. Undoubtedly the skull, viewed as the bony capsule
which encloses our most important organ of sense, our brain, has a
special claim to morphological importance; for the general
conformation of the skull corresponds on the whole to the development
of the brain, and its inner surface gives an approximate idea of the
outer surface of the brain. In this correspondence lies the only sound
kernel of the sickly, overgrown fancies of phrenology. The various
development of the skull allows of an approximate inference as to the
various degrees of development of the brain and of the mental
faculties. The comparative study of the skulls of the vertebrate
animals had excited the lively interest of morphologists by the end of
the last century, when comparative anatomy was beginning to
constitute a special science; and the genetic inquiry as to the
morphological significance and development of the skull soon grew out
of it. It was no less a man than our greatest German poet who first
answered this question, and propounded the theory that the skull was
neither more nor less than the modified foremost end of the vertebral
column, and that the separate groups of bones which lie behind one
another in the human skull, as in that of all the higher vertebrata,
answer to the separate modified vertebræ. This "vertebral theory" of
the skull, which Von Goethe and Oken simultaneously and independently
attempted to prove, aroused universal interest and maintained its
ground for seventy years, while many attempts were made to improve and
enlarge upon it in detail.

A quite new light was thrown on this, as on every other morphological
question, as soon as Darwin in 1859 had once more put into our hands
the torch of the doctrine of descent. The inquiry as to the origin of
the skull now assumed a real and tangible form. Since all vertebrate
animals, from fishes up to man, agree so completely as to their
essential internal structure that they can be rationally conceived of
no otherwise than as branches of one stock and as descendants of one
parent-form, the distinctly formulated question as to the skull
theory which now started into prominence was this: "How, historically,
has the skull of man and of the higher animals originated from that of
the lower animals? How is the development of the bones of the skull
from the vertebræ to be proved?" The answer to these difficult
questions was supplied by the first comparative anatomist of the
present day, by Carl Gegenbaur. After Huxley had pointed out that the
ontogenesis or individual development of the skull by no means
favoured the older hypothesis of Goethe and Oken, Gegenbaur brought
forward evidence that the fundamental idea of that theory was correct;
that the skull does in fact correspond to a series of coalescent
vertebræ, but that the separate bones of the skull are not to be
regarded as representing parts of such modified vertebræ. The
skull-bones of all recent vertebrate animals are rather, for the most
part, dermal bones, which have come into closer connection as
supplementary to the cartilaginous primitive skull. We can even now
trace the number and position of the original vertebræ, from which
this primitive skull originated, by the number of the vertebral arches
(gill-arches) which are attached to it, as well as by the number and
position of those vertebræ, from nine to ten. Of all the recent
vertebrata, the cartilaginous fishes, or Selachians, have most nearly
preserved the form and structure of this primordial skull. These
Selachians, the Rays and Sharks, are on the whole the creatures which
throw the clearest light on the history of the lineage of the
vertebrata and on the organisation of our primeval fish-natured
ancestors. It is one of the particular merits of Gegenbaur that he
clearly and firmly established the place in nature of the Selachians
as the common ancestors of all vertebrate animals from fish up to man.

None but those who have thoroughly studied the comparative morphology
of the vertebrata, who have sought the genetic issue from that
labyrinth of intricate morphological problems at the hands of the
theory of descent, can duly value the immeasurable service which
Gegenbaur has done by this and other "Investigations into the
Comparative Anatomy of the Vertebrata." These investigations are as
much distinguished by a profound knowledge and careful working out of
the wonderfully-extensive empirical materials for the subject, as by
their critical acumen and philosophic grasp. At the same time they set
in the clearest light the immeasurable value of the theory of descent
in the causal explanation of the most difficult morphological
problems. Gegenbaur might, therefore, with perfect right, enunciate
this axiom in the Introduction to his "Comparative Anatomy." "The
theory of descent will at once find a touchstone of proof in
comparative anatomy. Up to this time no experience in comparative
anatomy has transpired which contradicts that theory; on the
contrary, they all lead up to it. Thus it will receive back from
science that which it has given to scientific method: clearness and
certainty." In point of fact we can adduce no morphological
investigations which better support this declaration than those very
phylogenetic researches "as to the cranium of the Selachians, as a
basis for the critical examination of the genesis of the cranium of
the vertebrata," 1872. As Virchow had formerly thoroughly studied the
old skull-hypothesis, and in his admirable discourse on "Goethe as a
Naturalist," 1861, had given an excellent exposition of it; as
moreover he had produced most valuable contributions to the normal and
pathological anatomy of the human skull, we might have expected that
he would have received Gegenbaur's grand reform of the theory of the
skull, and historical solution of the skull-problem, with the greatest
interest, and have made it the clue to his own further researches. But
we seek in vain through Virchow's latest contributions to the study of
the human skull, for any indication of his knowing or appreciating
Gegenbaur's investigations. On the contrary, we see him persistently
moving, without any clear goal in view, on that trodden and devious
path of investigation which finds the highest aim of craniological
science in the measuring of skulls, or craniometry.

We are far from undervaluing the full significance of the results of
exact and careful descriptions and measurements of various
conformations of the skull as an empirical basis for a true and
scientific study of the skull--_i.e._, for comparative and genetic
craniology. But still we must say that the way and method by which
this skull measurement has, for ten years now, been pursued by
numerous craniologists can never yield corresponding scientific
results; on the contrary, though it is cried up as the "exact
morphology" of the skull, it simply loses itself in the domains of
harmless trifling. A large amount of time has in the last ten years
been squandered in disputes as to the best method of measuring skulls,
while the craniologists concerned have not, in the first place,
answered the obviously most important question: What end they propose
to gain by this specialist measuring, what proposition they mean to
prove by it? Most of those numerous skull measurers know nothing
beyond the perfect human skull, or at most the skulls of a few other
mammalia, while the comparative morphology and historical development
of the crania of the lower vertebrata are wholly unknown to them; and
yet these last contain the true key to the comprehension of the
others. One single month devoted by these "exact skull measurers" to
the study of Gegenbaur's theory of the skull, and to testing the
hypothesis by the skulls of Selachians, would have yielded them more
fruit and have given them more light than long years of describing and
measuring human skulls, however various.

Virchow himself affords the most striking example of the usual results
of this so-called "exact method" of studying skulls. In his popular
essay on "The Skulls of Men and Apes," 1870, he concludes with this
notable proposition:--"It is therefore self-evident that Man can never
by any progressive development have originated from the Apes." Every
evolutionist who is familiar with the surprising facts of comparative
morphology will draw from them the opposite conclusion: "It is
self-evident that Man could only have originated from the progressive
development of the Ape (organism)."

This brings us to that question which, in the popular treatment of the
theory of descent, is justly considered as its most important outcome
and as the keystone of the evolutionist edifice--to the well-known
proposition, "Man is descended from the Ape." While we simply ignore
all the misrepresentation, distortion, and misinterpretation which
this ape, or pithecoid hypothesis, has met with on all sides, we will
only remark that this fundamental proposition, in the sense of our
modern doctrine of evolution, can rationally have only this plain
meaning: that the human species as a whole was long since developed
from the order of apes, indeed actually from one (or perhaps more)
long since extinct form of ape; the immediate progenitors of man in
the long series of his vertebrate ancestry were apes or ape-like
animals. Of course none of the now surviving species of apes is to be
regarded as the unaltered posterity of that primeval parent-form.
Virchow, however, understanding the "ape question" in this sense,
answers it, as Bastian also does, with the most positive
contradiction. "We cannot teach the doctrine that man is descended
from apes or from any other animal, for we cannot regard it as a real
acquisition of science" (p. 31). Although I myself, in direct
opposition to this view, and in agreement with almost all my
professional colleagues, look upon the descent of man from apes as one
of the surest of phylogenetic hypotheses, I will here expressly admit
that the _relative_ certainty of this, as of all other historical
hypotheses of descent, is not comparable with the _absolute_ certainty
of the general theory of descent. It is now ten years since I first
explicitly stated (in my "Natural History of Creation," vol. ii. p.
358): "The pedigree of the human race, like that of every animal or
plant, remains in detail a more or less approximate general
hypothesis. This, however, in no way affects the application of the
theory of descent to man. In this, as in all researches into the
derivation of our organism, we must distinguish between the _general
theory_ of descent and the _specific hypothesis_ of descent. The
general theory of descent claims full and permanent value, because it
is inductively based on the whole range of common biological phenomena
and on their internal causal connection. Each special hypothesis of
descent, on the other hand, is conditional as to its specific value on
the existing state of our biological information, and on the extent of
those objective empirical grounds on which we deductively found the
hypothesis, by our subjective inferences." And I must here
emphatically add that I have on every opportunity repeated that
reservation, and have always insisted on the difference which exists
between the absolute certainty of transmutation in general and the
relative certainty of each individual specific pedigree. So that when
Semper and others of my opponents assert that I teach my specific
genealogies as "infallible dogmas," it is simply false. I have, on the
contrary, pointed out on all occasions that I regard them only as
_heuristic or provisional hypotheses_, and as a means of investigating
the actual relations of cognate races of organic forms more and more

Since the conception of the natural animal system as a hypothetical
genealogical tree, and the phylogenetic interpretation of
morphological affinity which that conception involves, afford in fact
the only rational interpretation of that affinity in general, my first
genealogical attempts soon found many imitators, and at the present
time numerous industrious labourers in the different departments of
systematic zoology are endeavouring to find in the construction of
such hypothetical genealogies the shortest and completest expression
of the modern conception of structural affinity. If Virchow had not
been as ignorant of the true significance and method of systematic
morphology as he is of its progress and scientific contents, he must
certainly have known this, and then he would surely have withheld his
mockery of all these grave phylogenetic studies as "personal
crotchets" and worthless dreams.

What mighty strides towards a mechanical morphology we have made by
this phylogenetic working out of the system, and how much light and
life it has at once thrown into the system that before was dead and
cold, can only be known to those who have long and deeply studied
specific systematisation and the grouping of species; Virchow has not
the remotest suspicion of it. Moreover, these attempts have now
proceeded so far, that a large proportion of the phylogenetic
hypotheses are regarded as very nearly certain, and can hardly
undergo any further essential modifications; while the greater number
of them are still in an unfixed state, and one systematist tries to
improve them in this direction, and another in that.

The following phylogenetic hypotheses are held to be almost
certain:----The descent of many-celled animals from single-celled, of
the Medusæ from the hydroid Polyps, of the jointed from the unjointed
worms, of the sucking from the gnawing insects, of amphibious animals
from fishes, of birds from reptiles, of the placental mammalia from
the marsupials, and so forth. I personally consider the descent of man
from the apes as equally certain; nay, I regard this most important
and pregnant genealogical hypothesis as one of those which, up to the
present time, rest on the best empirical basis.

Huxley, in particular, fifteen years ago, in his celebrated "Man's
Place in Nature," 1863, so admirably proved the undoubted "descent of
man from apes," and so clearly discussed all the relations that had to
be taken into consideration, that very little was left to others to
do. The result of his comparative morphological investigations is
contained in this proposition----" If we take up a system of organs,
be it which we will, the comparison of its modifications throughout
the series of apes leads us to the same conclusion: that in every
single visible character man differs less from the higher apes than
these do from the lower members of the same order." It is therefore
impossible for any objective zoologist, according to the principles of
comparative systematisation, to ascribe to man any other place in the
animal world than in the order of apes; and it is quite immaterial
whether we designate this individual group as the Order of Apes, or,
with Linnæus, as the Primates. For the phylogenetic construction of
the system, the common descent of man and of apes from one common
parent-form, necessarily follows from this inevitable grouping,
and on this proposition only all the general inferences of the
"ape-hypothesis" depend. As to what that common parent-form of men and
apes may have been, very different views might probably be brought on
opposite sides; but any one who knows the collected facts that bear
upon the matter, and estimates them impartially, must, in conclusion,
arrive at the certain conviction that that hypothetical and long-since
extinct parent-form can only have been genuine apes; that is to say,
of the placental mammalian type, such as when we see them now living
before our eyes we unhesitatingly class, on the ground of their
zoological characters, as true apes, in the order of Apes or Primates.

In this, and all other sound phylogenetic hypotheses, we may most
easily attain to a conviction of their truth by taking into
consideration and comparison the other possible hypotheses. But in
fact no single opponent of the ape-hypothesis has been able to combat
it with any other phylogenetic hypothesis that has the faintest
glimmer of probability. Not one opponent has suggested, or can
suggest, any other animal form that can serve as our nearest ancestor
than the ape. No one has ever reproached me by saying that Mother
Nature has endowed me with too little imagination; on the contrary, I
am often accused of having a superfluity of that gift of the gods; but
I have often and repeatedly exerted my imagination to picture to
myself any known or unknown animal-form as the nearest parent-form to
man in the place of the apes, and have always found myself under the
necessity of falling back upon the stock of apes. Let me conceive of
the outward conformation and the internal structure of the nearest
mammalian ancestors of men as I will, I am always forced to
acknowledge that this hypothetical parent-form ranges under the
zoologically-conceived order of apes, and cannot possibly be separated
from the Simiadoe or Primates. If, in spite of this, any one chooses,
out of a "personal crotchet," to accept some other series of unknown
animal ancestors of man that have nothing to do with apes, that is but
a mere empty hypothesis floating in the air. Our ape-hypothesis, on
the other hand, is objectively and thoroughly proved by the essential
agreement of the internal bodily structure of man and of apes, and by
the identity of their embryonic development, as I have fully shown in
my "Evolution of Man" (chaps. xix. and xxvi.) The mode and manner in
which he here puts palæontology in the foreground, and throws on the
theory of descent the task of producing an unbroken gradation of
fossil transitional forms between the apes and man, is very indicative
of Virchow's ignorance of this zoological question--in which I, as a
professional zoologist, must decisively declare his incompetence. The
reasons why such a solution of the problem is not to be expected, the
extraordinary imperfection of the palæontological record, the natural
impediments to the palæontological evidence of the genealogical table,
have been so lucidly unfolded by Darwin himself (chaps. ix. and x. of
the "Origin of Species") that I am obliged once more to come to the
conclusion that Virchow has never read it with any attention.

Besides, long before Darwin, the gifted Lyell, the great originator of
modern geology, showed clearly and convincingly how, for many reasons,
the greater part of the fossil series must remain most imperfect, and
these reasons were at a later period so often and so fully discussed
(by myself among others, in chap. xv. of the "History of Creation,"
vol. ii. pp. 24-32) that it is wholly superfluous once more and in
this place to state these well-known and time-worn questions. It only
shows how little Virchow was acquainted with geology and palæontology,
and what a limited judgment he can form of these historical causal


[15] Vol. i. p. 293.



No attack in Virchow's Munich address surprised me so much, and none
so plainly betrayed the subversion of his most important scientific
views, as that which he directed against my observations on psychology
and cellular physiology. A mystic dualism in his fundamental views is
here revealed, which stands in the sharpest contrast to the mechanical
monism formerly upheld by the famous pathologist of Würzburg.

In my Munich discourse (p. 12), I had alluded to the "grand and
fruitful application which Virchow had made, in his system of cellular
pathology, of the cell-theory to the general province of theoretic
medicine;" and as a logical amplification of that idea, I asserted
emphatically that we must ascribe an independent soul-life to every
individual organic cell. "This conception is validly proved by the
study of infusoria, amoebæ, and other one-celled organisms; for, in
these individual, isolated, living cells we find the same
manifestations of soul-life--feelings, and ideas (mental images),
will and motion, as is in the higher animals compounded of many cells"
(p. 13). Virchow now rises up in the strongest protest against this
theory of a cellular sensibility, which I regard as the inevitable
consequence of his early views of cellular physiology; it is to him
"mere trifling with words." He combats with equal decisiveness "the
scientific necessity of extending the province of psychical processes
beyond the circle of those bodies in and by which we actually see them
exhibited." He further says, "If I explain attraction and repulsion as
psychical phenomena, I simply throw the psyche out of the window; the
psyche ceases to be a psyche." Finally he says, "I assert without any
hesitation that for us the sum total of psychical phenomena is
connected with certain animals only, and not with the collective mass
of all organic beings; nay, not even with all animals in general. We
have no ground as yet for speaking of the lowest animals as possessing
psychical properties; we find such properties only in the higher
grades, and with perfect certainty only in the very highest."

When I first read this and other astounding statements in Virchow's
paper, I involuntarily asked myself, "Can this be the same Virchow
from whom, twenty-five years ago, I learnt in Würzburg that the
soul-functions of man and animals depend on mechanical processes in
the soul-organs; that these organs are, like all other organs,
composed of cells, and that the functional activity of an organ is
nothing more than the sum of the activity of all the cells which
compose it? Is this the same Virchow whose most vital doctrine it was
that all the physical and psychical processes of the human organism
were to be referred to the mechanics of cell life; who supported the
view of the unity of all the phenomena of life with the same emphasis
with which we are now obliged to defend it against his attacks?"

In fact, and beyond a doubt, we have here a new proof of Virchow's
complete change in all fundamental scientific principles. For the
cellular psychology which I advance is only a necessary consequence of
the cellular physiology promulgated by Virchow. His present opposition
to the former is either a renunciation of the latter or an untenable
and inconsequent position. To explain this astonishing metapsychosis,
we shall do well first to glance at the soul in general, and then give
particular consideration to the cell-soul.

What is the Soul or Psyche? The innumerable different answers which
have been given to this crowning question of psychology, may
collectively, when freed from all extraneous matter, be brought
under two groups which we may shortly designate as the dualistic and
the monistic soul-hypothesis. According to the monistic (or
realistic) soul-hypothesis, the "soul" is nothing more than the sum
or aggregate of a multitude of special cell-activities, among which
sensation and volition--sensual perception and voluntary
movement--are the most important, the most common, and the most
widely diffused; associated with these in the higher animals and in
man, we find the more developed activities of the ganglionic cells
which are included under the conceptions of Thought, Consciousness,
Intellect, and Reason. Like all the other functional-activities of
the organic cells, these soul-functions depend ultimately on
material phenomena of motion, and more particularly on the motions
of the plasson-molecules or plastidules, the ultimate atoms of the
protoplasma, and perhaps of the nucleus also; therefore we should be
able actually to grasp and explain them, as well as every other
cognisable natural process, if we were in a position to refer them
to the mechanics of atoms. This monistic soul-hypothesis, then, is
at bottom mechanistic. If psychical mechanics--psychophysics--were
not so infinitely complex and involved, if we were in a position to
take a complete view of the historical evolution of the psychic
functions, we could reduce the whole of them (including
consciousness) to a mathematical "soul-formula."

According to the opposite, or dualistic (or spiritualistic)
soul-hypothesis, the soul is, on the contrary, a peculiar substance,
which most people somewhat grossly conceive of as a gaseous body,
while others picture it with more subtlety, as an immaterial essence.
This "soul-substance" subsists independently of the animal-body, and
stands in only a temporary connection with certain organs of that
body--the soul-, or mental-organs. It has been imagined that this
soul-matter, which resembles that imponderable ether which is the
medium of light, is diffused between the ponderable molecules of the
soul-organs and especially of the nerve-cells, and that this
connection of the imponderable "soul" with the ponderable body
subsists only so long as the individual life lasts. At the instant of
the first beginning of the individual organism, at the moment of
generation, this imponderable "soul" passes into the body, and at the
instant of death, at the annihilation of the living individual, it
again quits the body. This mystical or dualistic soul-hypothesis,
which, as is well known, is to this day universally accepted, is
fundamentally vitalistic, inasmuch as it regards the force which is
bound up with the soul-substance, like the "vital force" of a past
time, as a peculiar force quite independent of mechanical forces. This
force does not depend on the material phenomena of motion, and is
quite independent of the mechanics of atoms. The highest law of modern
natural science, the law of the conservation of force, has,
therefore, no application in the region of soul-life, and that
mechanical causality which prevails throughout all the processes of
nature does not exist for the soul. The Psyche, in a word, is a
supernatural phenomenon, and the supernatural department of the
spiritual world stands free and independent of the natural department
of the material world.

If we now compare the psychological views of the youthful and
unprejudiced Virchow of Würzburg with those of the older and mystical
Virchow of Berlin, there can be no doubt in the minds of the impartial
that the former, a quarter of a century ago, was as decided and
logical a monist as the latter is at present a confessed and convicted
dualist. The distinguished position which Virchow, twenty-five years
since, won by his natural conception of the nature of man, and the
great fame which he then earned in the fight for the truth, rest
precisely on this, that on every occasion he maintained with his
utmost vigour the unity of all vital phenomena, and asserted their
mechanical character. All organic life, even the soul-life, rests on
mechanical principles, on that causal mechanism of which Kant said
that "it alone contained a practical interpretation of nature," and
that "without it no natural science can exist." On this point Virchow
says well in his discourse on "Efforts at Unity in Scientific
Medicine," 1849:--"Life is only a peculiar sort of mechanics, though
it is indeed the most complex form of mechanics; that in which the
usual mechanical laws fall under the most unusual and manifold
conditions. Thus life, compared with the universal processes of motion
in nature, is a thing peculiar in itself; but it does not constitute a
diametrical, dualistic opposition to those laws; it is only a peculiar
species of motion. The motion itself is a mechanical one, for how
should we become cognisant of it if it were not based on the sensible
properties of bodies? The media of the motion are certain chemical
matters, for we recognise none but chemical matter in bodies. The
individual acts of motion reduce themselves to mechanical, or
physico-chemical, modifications of the constituent elements of the
organic unities, the cells and their equivalents." These and many
similar utterances in Virchow's earlier writings, and especially in
the essay I have mentioned, "On the Mechanical Conception of Life,"
leave no doubt that he formerly supported, with a clear conscience and
his utmost energy, in psychology as in the other collected departments
of physiology, that very mechanical standpoint which we to-day accept
as the essential basis of our monism, and which stands in
irreconcilable antagonism to the dualism of the vitalistic doctrine.
To none of my teachers am I so deeply indebted for my emancipation
from all the prejudices of the dualistic doctrine, and for my
conversion to the monistic, as to Rudolf Virchow; for it was his
superior guidance which most firmly convinced me, and many others, of
the exclusive importance of the mechanical view of nature. He led me
to a clear recognition of the fact that the nature of man, like every
other organism, can only be rightly understood as a united whole, that
this spiritual and corporeal being are inseparable, and that the
phenomena of the soul-life depend, like all other vital phenomena, on
material motion only--on mechanical (or physico-chemical)
modifications of cells. And it was in perfect agreement with my most
honoured master that I subscribed then, and at this day still
subscribe, to the proposition with which he, in September 1849, closed
the preface to the above-mentioned "Efforts at Unity." "It is possible
that I may have erred in details; in the future I shall be ready and
willing to acknowledge my mistakes and to rectify them, but I enjoy
this conviction, that I shall never find myself in the position of
denying the principle of the unity of the human nature with all its

To err is human! Who can say to what diametrical contradiction to his
firmest convictions man may not in the future be driven by his
adaptation to new relations in life? If we compare these stout
monistic declarations of 1849 and 1858 with the equally decided
dualistic utterances in Virchow's Munich address of 1877, we perceive
that he could not give the lie more fiercely to his former fundamental
opinions than he has there done. Not quite twenty years have passed
by, and yet, in the course of that time, in Virchow's views of the
universe, in his conception of human nature, and of the soul-life, a
change has been effected than which we can conceive of no greater. We
learn to our surprise that psychical and corporeal processes are
wholly different phenomena; that no scientific necessity whatever
exists for extending the province of psychical processes beyond the
circle of those bodies in which, and by which, we see them actually
exhibited. "We may ultimately explain the processes of the human mind
as chemical, but at any rate, it is not yet our business to amalgamate
these two subjects!"

From the whole psychological discussion which is involved in Virchow's
Munich address, it is made clear that at the present time he regards
the "soul" in a purely dualistic sense as a substance, an immaterial
essence which only temporarily takes up its abode in the body. Highly
characteristic of this is the remarkable sentence, "If I explain
attraction and repulsion as psychical phenomena, I simply throw the
psyche out of the window; the psyche ceases to be a psyche." If we
substitute for the word "psyche" the word which corresponds to
Virchow's earlier mechanistic view--the word "motion" (or peculiar
mode of motion)--the sentence runs thus: "If I explain attraction and
repulsion as phenomena of motion, I simply throw motion out of the

Almost more remarkable is Virchow's assertion that the lowest animals
have no psychic properties; that, on the contrary, "these are only to
be found in the higher, and, with perfect certainty, only in the
highest animals." It is only to be regretted that Virchow has not here
stated what he understands by the higher and the highest animals;
where that remarkable dividing line is, beyond which the soul suddenly
appears in the hitherto soulless body. Every zoologist who is in some
degree familiar with the results of comparative morphology and
physiology will here clasp his hands in astonishment, for by this
proposition Virchow seems to mean that we must ascribe a soul-life
only to those animals in which special soul-organs, in the form of a
central and peripheral nerve-system, are developed from sense-organs
and muscles. But it is admitted that all these different soul-organs
with their characteristic properties have originated from single cells
through the division of labour (differentiation); and the nerves and
muscles especially have been developed by differentiation from the
neuro-muscular cells. The cells from which all these different
nerve-cells, muscle-cells, mind-cells, and so forth, are derived, are
originally the simple neutral cells of the epithelium of the ectoderm
or exterior germ-layer, and these cells, again, like all the cells of
many-celled animal bodies, originated in the repeated division of one
single original cell, the ovum-cell.

The individual development or ontogenesis of each of these many-celled
animal-forms, brings this histological process of development so
clearly and evidently before our eyes that we can but directly infer
from it the truth of the phylogenesis, or gradual historical evolution
of the soul-organs. The association of cells and the division of
labour among them are the modes by which, in the first instance, the
compound many-celled organism has originated, historically, from the
simple one-celled organism. And an impartial comparative consideration
teaches us in the clearest way that a functional-activity of the
soul-cells exists in the lowest one-celled animals as well as in the
highest and many-celled; in the infusoria as well as in man. Volition
and sensation, the universal and unmistakable signs of soul-life, may
be observed among the former as well as in the latter. Voluntary
motion and conscious sensation (of pressure, light, warmth, &c.) come
under our observation so undoubtedly in the commonest forms of
infusorial animals--for instance the Ciliata, that one of their most
persevering observers, Ehrenberg, asserted undeviatingly to the day of
his death that all Infusoria must possess nerves and muscles, organs
of sense and of soul, as well as the higher animals.

It is well known that the enormous advance which our science has lately
made in the natural history of these lowest organisms culminates in the
statement--clearly made by Siebold thirty years since, but only recently
"ascertained as proved"--that these minute creatures are _one-celled_,
and that in the case of these infusoria one single cell is capable of
all the various vital functions--including soul-functions--which in the
zoophytes (plant-animals), as the hydra and the sponges, are distributed
among the cells of the two germ-layers, and in all the higher animals
among the different tissues, organs, and apparatus of a highly developed
and constructed organism. The psychic functions of sensation and
voluntary motion, which are here distributed to such very various organs
and tissues, are in the infusoria fulfilled by the neutral plasson
material of the cell, by the protoplasma, and possibly also by the
nucleus (compare my treatise "The Morphology of the Infusoria." Jena,
Zeitschriften, 1873, vol. vii. p. 516). And just as we must attribute to
these primary animal forms an independent "soul," just as we must
plainly be convinced that the single independent cell has a "psyche," we
must as decidedly attribute a soul to every other cell; for the most
important active constituent of the cell, the protoplasm, everywhere
exhibits the same psychic properties of sensibility or irritability, and
motive power or will. The only difference is this, that in the organism
of the higher animals and plants the numerous collected cells, to a
great extent, give up their individual independence, and are subject,
like good citizens, to the soul-polity which represents the unity of the
will and sensations in the cell community. We here also must distinguish
clearly between the central soul of the whole many-celled organism or
the personal psyche (the person-soul), and the particular individual
soul or elementary soul of the individual cells constituting that
organism (the cell-soul). Their relations are strikingly illustrated in
the instructive group of Siphonophora, as I have briefly shown in my
article on "The Cell-soul and Soul-cells" (Deutsche Rundschau, July
1878). Beyond a doubt the whole stock or polity of Siphonophora has a
very definite united will and a united sensibility, and yet each of the
individual persons of which this stock (or Cormus) is composed has its
own personal will and its own particular sensations. Each of these
persons indeed was originally a separate Medusa, and the individual
Siphonophora stock originated, by association and division of labour,
out of these united Medusa communities.

When I developed this theory of the cell-soul and designated it in my
Munich address as the "surest foundation of empirical psychology," I
believed I was drawing an inference quite to Virchow's mind, from his
own views of mechanical and cellular-physiology; and for that reason I
took the same occasion specially to celebrate his very great services
to the cell theory. How astonished then was I when in his reply this
very theory was violently attacked and satirised as "mere trifling
with words." It never could have occurred to me that Virchow had long
since become unfaithful to his most important biological principles,
and had deserted his own mechanical "theory of cells;" it never had
occurred to me that Virchow could be in great measure wanting in that
zoological knowledge which is requisite for a practical comprehension
of the cell-soul theory. He has never thoroughly studied either the
one-celled Protozoa, the Infusoria and Lobosa, nor the Coelenterata,
the highly instructive Sponges, Hydroids, Medusæ, or Siphonophora; and
thus he is wanting in those genetic principles of comparative zoology
on which our theory rests. It is in no other way conceivable that
Virchow should contemn the most important consequences of the cell
theory as "mere trifling with words."

Next to the one-celled infusoria no phenomenon throws such direct
light on our cellular psychology as the fact that the human ovum, like
the ova of all other animals, is a single, simple cell. In accordance
with our monistic conception of the cell-soul, we must conclude that
the fertilised ovum-cell already virtually possesses those psychical
properties which, by the special combination of the peculiarities
inherited from both parents, characterise the individual soul of the
new person; in the course of the development of the germ, the
cell-soul of the fertilised ovum naturally is developed simultaneously
with its material substratum, and subsequently, after birth, it
appears in full activity.

According to Virchow's dualistic conception of the psyche, we must, on
the contrary, assume that this immaterial essence at some period of
its embryonic development (apparently when the spine separates itself
from the external germ-layer) informs the soulless germ. Of course,
the bare miracle is thus complete, and the natural and unbroken
continuity of development is superfluous.



The very justifiable surprise which Virchow's Munich address has
excited in many circles is due only in part to his opposition to the
theory of descent; for the rest, and in much greater part, it is due
to the astounding arguments which he has connected with it,
particularly as to freedom for instruction. These arguments so closely
resemble those of the Jesuits that they might have been inspired
direct from the Vatican, or, which is the same thing, the notorious
"court-chaplain party" in Berlin. No wonder, then, that these
propositions, which would undermine the whole liberty of science, have
met with the loudest approbation from the "Germania," the "New
Evangelical Church Times" ("Neue Evangelischen Kirchenzeitung"), and
other leading, equivocating organs of the Church militant. On the
other hand, these odious principles are already so extensively
discussed, and have been so clearly laid down in all their
indefensibility, that I may here deal with them briefly.

Virchow's politics as a pedagogue reach their highest pitch in this
demand: "that in all schools, from the poor schools to the
universities, nothing shall be taught that is not absolutely certain.
None but objective and absolutely ascertained knowledge is to be
imparted by the teacher to the learner; nothing subjective, no
knowledge that is open to correction, only facts, no hypotheses." The
investigation of such problems as the whole nation may be interested
in must not be restricted; that is liberty of inquiry; but the problem
ought not, without anything farther, to be the subject of _teaching_.
"When we teach we must restrict ourselves to the smaller, and yet how
great, departments which we are actually masters of."

Rarely indeed has such a treasonable attempt on liberty of doctrine
been made by a prominent representative of science, and a leader of
the intellectual movement too, as this by Virchow. Only inquiry is to
be free and not teaching! And where in the whole history of science is
there one single scientific inquirer to be found who would not have
felt himself quite justified in teaching his own subjective
convictions with as much right as he had to construct them from
inquiry into objective facts. And where, generally speaking, is the
limit to be found between objective and subjective knowledge? Is
there, in fact, any objective science?

This question Virchow answers in the affirmative, for he goes on to
say: "We must not forget that there is a boundary line between the
speculative departments of natural science and those that are actually
conquered and firmly established" (p. 8). In my opinion, there is no
such boundary line; on the contrary, all human knowledge as such is
subjective. An objective science which consists merely of facts
without any subjective theories is inconceivable. For evidence in
favour of this view we must take a rapid survey of the whole domain of
human science, and test the chief departments of it to see how far
they contain, on the one hand, objective knowledge and facts, and on
the other, subjective knowledge and hypotheses. We may begin directly
with Kant's assertion that in every science only so much true--that is
objective--knowledge is to be found as it contains of mathematics.
Unquestionably mathematics stand at the head of all the sciences as
regards the certainty of its teaching. But how as to those deepest and
simplest fundamental axioms which constitute the firm basis on which
the proud edifice of mathematical teaching rests? Are these certain
and proved? Certainly not. The bases of its teaching are simply
"axioms" which are incapable of proof. To give only one example of how
the very first principles of mathematics might be attacked by
scepticism and shaken by philosophical speculation, we may remember
the recent discussions as to the three dimensions of space and the
possibility of a fourth dimension; disputes which are carried on even
at the present day by the most eminent mathematicians, physicists, and
philosophers. So much as this is certain, that mathematics as little
constitute an absolutely objective science as any other, but by the
very nature of man are subjectively conditioned. A man's subjective
power of knowing can only discern the objective facts of the outer
world in general so far as his organs of sense and his brain admit in
his own individual degree of cultivation.

However, granting that mathematics practically constitute an
absolutely certain and objective science, how is it with the rest of
the sciences? Undoubtedly the most certain among them are those "exact
sciences" whose principles are to be directly proved by mathematics;
thus, in the first place, a great part of physics. We say, "a great
part," for another large part--to speak accurately, by far the
greatest--is incapable of any exact mathematical proof. For what do we
know for certain of the essential nature of matter, or the essential
nature of force? What do we know for certain of gravitation, of the
attraction of mass, of its effects at great distances, and so on?
Newton's theory of gravitation is regarded as the most important and
certain theory of physics, and yet gravitation itself is a hypothesis.
Then, as to the other branches of physics--electricity and magnetism.
The whole scheme of these important sciences rests on the hypothesis
of "electric fluidity," or of imponderable matter of which the
existence is nothing less than proved. Or optics? Optics certainly
appertain to the most important and completest branch of physics, and
yet the undulatory theory of light, which we accept now as the
indispensable basis of optics, rests on an unproved hypothesis, on the
subjective assumption of an ethereal medium, whose existence no one is
in a position to prove objectively in any way. Nay, further, before
Young set up the undulatory theory of light, for a hundred years the
emanation theory as taught by Newton obtained exclusively in physics;
a theory which at the present day is universally regarded as
untenable. In our opinion the mighty Newton won the greatest honours
in the development of the science of optics, inasmuch as he was the
first to connect and explain the vast mass of objective optical facts
by a subjective and pregnant hypothesis. But, according to Virchow's
view, Newton on the contrary transgressed greatly by teaching this
erroneous hypothesis; for even in "exact" physics none but
"independent and certain facts" are to be taught and established by
"experiment as the highest means of proof." Physics as a whole, as
resting on mere unproved hypotheses, may be indeed an object of
inquiry but not of teaching.

Of course the same is true of chemistry; nay, this stands on much
weaker feet, and is even less proved than physics. The whole
theoretical side of chemistry is an airy structure of hypotheses such
as does not exist in any other science. In the last three decades we
have seen a whole series of the most different theories rapidly
succeed each other, none of which can be positively proved, though at
least one of them is taught by every professor of chemistry. But what
is worst of all, the common basis of all the most dissimilar chemical
theories, viz., the atomic theory, is as unproved and unprovable as
any hypothesis can be. No chemist has ever seen an atom, but he
nevertheless considers the mechanism of atoms as the highest term of
his science, he nevertheless describes and constructs the connection
of atoms in their various combinations as though he had them before
him on the dissecting-table! All the conceptions which we possess as
to chemical structure and the affinities of matter, are subjective
hypotheses, mere conceptions as to the position and changes of
position of the various atoms, whose very existence is incapable of
proof. Away, then, with chemistry from our schools! The chemist must
only describe the properties of the different elements and those
combinations which can be put before the pupil as ascertained facts
founded in experiment, "the highest means of proof." Everything that
goes beyond this is mischievous, particularly every suggestion as to
the essence and chemical constituents of bodies; matters as to which,
in the nature of things, we can only form uncertain hypotheses. For as
all chemistry, viewed as a system of doctrine, rests solely on such
hypotheses, it may be indeed a subject of investigation but not of

Having thus convinced ourselves that chemistry as well as physics,
those "exact sciences," those "mechanical" bases of all other
sciences, rest on mere unproved hypotheses, and so must not be taught,
we may make short work of the other faculties. For they collectively
are more or less historical sciences and dispense wholly or in part
with even those half-exact, fundamental principles on which physics
and chemistry are based. In the first place, there is that grand,
historical, natural science, geology; the great doctrine of the
structure and composition, the origin and development of our globe.
According to Virchow this too must be limited to the description of
ascertained facts, such as the structure of mountain masses, the
character of the fossils they contain, the formation of crystals, and
so forth. But not for the world must anything be taught as to the
evolution of this globe; for this rests from beginning to end on
unproved hypotheses. For even to the present day the Plutonic and
Neptunic theories are disputing the field, and to this day we know not
as to many of the most important rocks, whether they originated by the
agency of fire or of water. The new and remarkable discoveries of the
great Challenger-expedition threaten to subvert a great many
geological notions which had long been regarded as certain. Then
again, as to fossils. Who can prove with any certainty that these
petrifactions are in truth the fossilised remains of extinct
organisms? They may be--as many distinguished naturalists of even the
last century maintained--marvellous sports of nature, mysterious
"Lusus naturæ," or mere rough, inorganic models of the labouring
Creator into which He subsequently "breathed the breath of life;" or
perhaps "stone-flesh" (caro fossilis) brought into existence, on the
dead rocks by the "fertilising air" (aura seminalis), and so forth.

But I am wrong! for with regard to petrifactions, Virchow is in the
highest degree speculative, and accepts without any hesitation the
rash hypothesis that fossils are actually the remains of extinct
organisms, although no "certain proof" whatever can be offered in its
favour, and although experiment, the "highest means of proof," has
never yet produced a single fossil. According to him these are actual
"objective, material evidences," only here we must go no further than
certain experience teaches us, and base no subjective conclusions on
these objective facts. Thus, for instance, in the long series of the
mesozoic formations, in the different strata of the Trias, Jurassic,
and Chalk formations, for the deposition of which a lapse of many
millions of years has been required, we find absolutely no remains of
fossil mammalia beyond lower jaws; seek where we will, nothing is
anywhere to be found but lower jaws, and no other bones whatever. The
simple reasons of this striking imperfection of the palæontological
record have been clearly expounded by Lyell, Huxley, and others.
(Comp. my "History of Creation," vol. ii. p. 32.) These great
investigators, in accordance with all other palæontologists, have
demonstrated that these jaw-bones of the mesozoic period are the
remains of mammalia, accurately speaking of marsupials, on the simple
ground that the nether jaws of the extant recent marsupials show a
similar characteristic form with the fossil ones. They therefore
unhesitatingly assume that the rest of the bones in the bodies of
these extinct animals corresponded to those of living mammals. But
this is a quite inadmissible hypothesis devoid of any "certain proof!"
Where, then, are the other bones? Let us see them! till then we
decline to believe in them. According to Virchow, we ought rather to
assume that the lower jaw was the only bone in the body of these
extraordinary beasts. Are there not, in fact, snails, in which an
upper jaw is the only representation of a skeleton.

We cannot omit taking this opportunity of casting a side glance at the
very hazardous position which Virchow, in total opposition to his
boasted cool scepticism, has taken up in anthropology as it is called,
now his favourite branch of science. In his Munich address he tells us
that he is pursuing the study of anthropology with delight, and then
asserts that "the quarternary man" is an universally-accepted fact.
Quite apart from this statement, we have seen that Virchow can never
attain to a profound and really scientific study of anthropology
simply for this reason, that he is lacking in that comprehensive
knowledge of comparative morphology which is indispensable to it; nay,
comparative anatomy and ontogenesis must be, according to him,
unpermitted speculations and the phylogenesis of man, the key to all
the most important questions of anthropology, being based upon these,
is devoid of all certain proof. All the more must we wonder at the
speculative levity with which even the sceptic Virchow in the
"Primeval History of Man" and "Fossil Anthropology," embarks in the
most hazardous conjectures, and gives out uncertain, subjective
hypotheses as certain, objective facts.

There is, in fact, at the present day no department of science in
which the wildest and most untenable hypotheses have blossomed out so
freely as in anthropology and ethnology, so-called. All the
phylogenetic hypotheses which I myself have put forward in my
"Evolution of Man" as to the animal ancestry of man, or in my "Natural
History of Creation" as to the affinities of animal races--all the
other genealogical hypotheses which are now advanced by numerous
zoologists and botanists as to the phylogenetic evolution of the
animal and plant worlds--all these hypotheses together, which Virchow
rejects in a lump, are, critically considered as hypotheses, far
better grounded in facts, far better supported by facts, than the
majority of those innumerable airy and fanciful hypotheses with which,
for the last twelve years, the "Archiv für Anthropologie" and
"Zeitschrift für Ethnologie," edited by Virchow and Bastian, have
filled their columns. This last periodical has at least the merit of
being a tolerably consistent opponent of the doctrine of evolution,
while in the former, during twelve years, essays on both sides have
been mixed up in cheerful confusion. And how fanciful are the
short-sighted hypotheses which there blossom forth from the mixed mass
of facts, chaotically flung together. Only think of the disputes over
the stone age, bronze age, and iron age; think of the motley
discussions as to the varieties of skull-conformation and their
significance; on the races of man, the migrations of peoples and the
like. Most of these very intricate historical problems are far more
buried in obscurity, and the hypotheses to explain them dispense far
more largely with any basis of facts, than is the case with our
phylogenetic hypotheses; for these are more or less "objectively"
based on the facts of comparative anatomy and ontogenesis.

But no one of these historical hypotheses is so daring, so little
"certainly proved," as the group of very various and contradictory
hypotheses which have been put forward as to the antiquity and first
appearance of the human species; and Virchow asserts positively "The
pleistocene man is an universally accepted fact. The tertiary man is,
on the other hand, a problem, though indeed a problem which is already
under substantial discussion!" As if the distinction between the
tertiary and quarternary periods were not itself a geological
hypothesis, and as if the significance of the fossil animal-remains,
which play the largest part in it, did not also rest on mere
hypotheses which escape all certain proof! Where, then, is the actual
experiment "as the highest means of proof," which gives evidence for
these "certain facts"? The whole discussion in general about
prehistoric man, which Virchow has mixed up with his Munich address
(pp. 30, 31), is the clearest evidence of the uncritical spirit in
which he deals with these historical problems as "exact natural
sciences." He assures us that "not one single ape's skull, nor skull
of an anthropoid ape, has ever been found which could actually have
belonged to a human owner!" and he adds this sentence, in italics, "We
cannot teach, for we cannot regard it as a real acquisition of
science, that man is descended from the ape or from any other animal!"
Then evidently no alternative remains but that he is descended from a
god, or from a clod!

But let us go over the rest of the sciences to see what, according to
Virchow, may be taught in each without endangering the safety of
science. In the whole department of biology, as well as in
zoology--including anthropology--and in botany, instruction must be
limited to imparting those trifling fragments of knowledge which
either consist of mere descriptions of dry facts, or which supply an
explanation of them by mathematical formulas. Morphology must be
taught as mere descriptive anatomy and systematising, the history of
development as mere descriptive ontogenesis. Comparative anatomy and
phylogenesis, which by their explanatory hypotheses raise those dead
masses of facts to the place of true and living sciences--these must
not be taught at all. And how then do matters stand with regard to the
cell-theory, that fundamental theory on which every element of our
morphology and physiology depends, and by applying which Virchow
himself reached his grandest results?

Since Schleiden in Jena, forty years ago, first put forward the
cell-theory, and Schwann immediately after applied it to the animal
kingdom and so to the whole organic world, this fundamental doctrine
has undergone very important modifications, for it is indeed a
biological theory, but not a fact. We may recollect under what
different aspects its main principles have appeared in the course of
these four decades: what changes have taken place in the conception of
the cell itself. After the organic cell had originally been conceived
of as a vesicle, consisting of a firm capsule and a fluid content, we
subsequently discerned it to be composed of a glutinous semi-fluid
cell-substance, the protoplasm, and convinced ourselves that this
protoplasm and the cell-core or nucleus enclosed in it are the most
important and indispensable constituent parts of the cell, while the
external firm capsule, the cell-membrane, is not essential and very
frequently wanting. But even now opinions widely differ as to how the
conception of a cell should be precisely defined, and what
consequences must be inferred from the cell-theory, and attempts have
not been wanting to upset it altogether and to treat it as worthless.
The anatomist Henle, of Göttingen, in particular, has repeatedly made
such an attempt, that "gifted" anatomist who, in the preface to his
bulky text-book of human anatomy, declared that scientific ideas are
mere worthless paper money, and that the noble metal of facts, on the
contrary, is the only genuine article. Not long since a bulky volume
in quarto appeared, by one Herr Nathusius-Königsborn, in which the
cell is explained to be a subordinate plastic element, and the
cell-theory is eliminated as superfluous; and this monstrous volume,
full of the most amusing nonsense, is dedicated to Herr Henle. Virchow
formerly was one of the victorious opponents of the Göttingen
physician, and wrote brilliant articles against the "rational
pathology" of "irrational Herr Henle;" now apparently he agrees with
him that the paper money of ideas is worthless as compared with the
noble metal of facts. Of course the cell-theory then loses all its
value, and cannot be a subject of instruction; for the cell itself is
not a certain and undoubted fact, but only an abstraction, a
philosophical idea.

Nothing more clearly shows what a complete change Virchow has
undergone in his most important principles, and what an utter
metapsychosis in this special province, than his famous axiom,
uttered in 1855--"Omnis cellula e cellula." That is unquestionably the
boldest generalisation to which the youthful, independent Virchow ever
attained, and one on which he justly prided himself not a little. He
himself repeatedly compared it with Harvey's saying, which marked an
epoch--"Omne vivum ex ovo." But neither of these axioms is universally
correct. On the contrary, we now know that every cell does not
necessarily originate from a cell, any more than that every organic
individual originates from an ovum. In many cases true nucleated cells
proceed from un-nucleated cytods, as in the Gregarinæ, Myxomycetæ and
others. Nay more, the primordial organic cells could only have
originated in the first instance from non-cellular plastides or monads
by their homogeneous plasson resolving itself into an internal nucleus
and an external protoplasm. Thus, as we subsequently learnt to know
most of the exceptions to this generalisation of Virchow, it appeared
all the bolder; the more so as we were at that time far from being
able to refer all the different tissues of the higher animals with any
certainty to cells, and as not a few experiments seemed to point to
the hypothesis of free cell-formation. That guiding axiom, which so
powerfully furthered the cell-theory, Virchow, from his present
standpoint, must wholly condemn as a crime against exact science, and
he surely can never forgive himself for having propounded this
hypothesis--which was afterwards found to be not universally true--as
an important doctrinal axiom.

We shall indeed find much worse sins against his own principles of
to-day if we turn to Virchow's own special department of science,
namely, pathological anatomy and physiology, the most important
division of theoretic medicine. The great and incomparable services
which Virchow here effected do not depend on the numerous independent
new facts which he discovered, but on the theories and hypotheses by
which, like an inspired pioneer, he sought to open a way through the
dead waste of pathological knowledge and to form it into a living
science. These new theories and the hypotheses on which they were
founded, Virchow then propounded to us, his disciples, with such
incisive assurance that every one of us was convinced of their truth;
and yet later experience has shown that they were in part
insufficiently proved and in part wholly false. For example, I will
only here recall his famous theory of the connective-tissue, for which
I myself in several of my early works (1856 to 1858) broke a lance.
His theory seemed to explain a host of the most important
physiological and pathological phenomena in the simplest manner, and
yet it was afterwards proved to be false. In spite of this, I declare
to this day that it was of the greatest service for the development of
our acquaintance with the formation of the connective-tissue; as a
guiding hypothesis and as a provisional clue to our investigations.
Virchow, on the contrary, if he impartially reflects on the part he
took in the diffusion of this misleading doctrine, must reproach
himself severely for it. For "we must draw a hard and fast line
between what we are to teach and what we are to investigate. What we
investigate are problems," but "the problem ought not to be the
subject of teaching." That Virchow, in his course of instruction,
every day belied this, his present view of teaching, that he every
hour taught his disciples some unproved theory and problematical
hypothesis, every one knows who, like myself, for years and with the
deepest interest, enjoyed his distinguished instruction. Still the
captivating charm of this instruction--in spite of the defective
method of unprepared lectures--lay precisely in this, that Virchow as
a teacher constantly let us, his pupils, enter into those problems
with which he himself at the moment was occupied; that he propounded
to us his personal hypothesis for the elucidation of the given facts.
And what really gifted teacher who lives in his science would not do
the same? Where is there, or where has there ever been, a great master
who in his teaching has confined himself to only imparting certain
and undoubtedly ascertained facts? Who has not, on the contrary, found
that the charm and value of his instruction lay precisely in
propounding the problems which link themselves with those facts, and
in teaching the uncertain theories and fluctuating hypotheses which
may serve to solve these problems? Or is there for the young and
struggling mind anything better, or more conducive to culture, than to
exercise the intelligence in problems of investigation?

How unpractical and how absurd is Virchow's demand--that only
ascertained facts and no problematic theories shall be admitted in
teaching--will be still more strikingly shown by a glance over the
remaining provinces of human knowledge. What, indeed, will be left of
history, of philology, of political science, of jurisprudence, if we
restrict the teaching of them to absolutely-ascertained and
established facts. What of "science" will remain to them if the idea
which endeavours to discern the causes of the facts is banished? if
the problems, the theories, the hypotheses, which seek these causes
may not be generally taught? And that philosophy--the science of
knowing--by which all the common results of human knowledge are to be
bound up into one grand and harmonious whole--that philosophy, I say,
must not be generally taught, is, according to Virchow, quite

Finally, there remains nothing but theology. Theology alone is the one
true science, and its dogmas alone may be taught as certain. Of
course! for it proceeds directly from revelation, and only divine
revelation can be "quite certain;" it alone can never err. Yes,
incredible as it sounds, Virchow, the sceptical opponent of dogma, the
leader of the fight for "liberty of science," Virchow now finds the
only sure basis for instruction in the dogmas of the Church. After all
that has gone before, the following memorable sentence leaves no doubt
on this score:--"Every attempt to transform our problems into dogmas,
to introduce our conjectures as a basis of instruction, particularly
any attempt simply to dispossess the Church and to supplant her dogma
by a creed of descent--ay, gentlemen--this attempt must fail, and in
its ruin will entail the greatest peril on the position of science in

The shouts of triumph of the whole clerical press over Virchow's
Munich address is thus rendered perfectly intelligible, for it is well
known that "there is more joy in heaven over one sinner that repenteth
than over ten just men." When Rudolf Virchow, the "notorious
materialist," the "advanced radical," the "great supporter of the
atheism of science," is so suddenly converted, when he proclaims
loudly and publicly that the dogmas of the Church are the only sure
basis of instruction, then the Church militant may well sing "Hosanna
in the highest!" Only one thing is to be regretted, that Virchow has
not more clearly defined which of the many different church-religions
is the only true one, and which of the innumerable and contradictory
dogmas are to form the sure basis of instruction. We all know that
each Church regards itself as the only truly saving one, and her own
dogma as the only true one. But as to whether it is to be
Protestantism or Catholicism, the Reformed or the Lutheran confession,
whether the Anglican or the Presbyterian dogma, whether the Roman or
the Greek Church, the Mosaic or the Mohammedan dispensation, whether
Buddhism or Brahmanism, whether, finally, it is to be one of the many
fetish-religions of the Indians and Negroes that is to form the
permanent and sure basis of instruction, let us hope that Virchow will
at the next meeting of German naturalists and physicians divulge his

At any rate, the "instruction of the future, according to Virchow," will
be greatly simplified if he will do this. For the dogma of the Trinity
in Unity as a basis of mathematics, the dogma of the resurrection of the
body as a basis of medicine, the dogma of infallibility as a basis of
psychology, the dogma of the immaculate conception as a basis of genetic
science, the dogma of the staying of the sun as a basis of astronomy, the
dogma of the creation of the earth, animals, and plants as a basis of
geology and phylogenesis--these or any other dogma, at pleasure, from any
other church will make all other doctrine quite superfluous. Virchow,
"that critical spirit," knows as well as I, and as every other naturalist,
that these dogmas are not true, and nevertheless, in his opinion, they
are not to be supplanted as the "basis of instruction" by those theories
and hypotheses of modern natural science of which Virchow himself says
that they may be true, that in a great measure they probably are true,
but are not yet "quite certainly proved."

At pages 15, 24, 26, 28, and elsewhere in his Munich address, Virchow
strongly insists that only that objective knowledge may be taught
which we possess as absolutely certain fact! and then at page 29 he
requires us to conclude that the basis of instruction shall continue
to be the purely subjective dogmas of the Church; revelations and
dogmas which not only are not proved by any facts whatever, but on the
contrary, stand in the most trenchant contradiction to the most
obvious facts of natural experience and fly in the face of all human
reason. These contradictions, to be sure, are no greater than some
others which stand out conspicuous and incomprehensible in Virchow's
discourse. Thus at the beginning of his address he glorifies Lorenz
Oken and deeply laments "that he, that highly-valued and honoured
master, that ornament of the high school of Munich, had been forced
to die in exile! That cruel exile which oppressed Oken's latter years,
which left him to perish far from those cities to which he had
sacrificed the best powers of his life, that exile will be remembered
as the note of the time which we have passed through. And so long as
there continue to be meetings of German naturalists, so long may we
gratefully remember that this man to his death bore upon him all the
signs of a martyr, so long shall we point to him as one of the
witnesses who have fought for us and for the liberty of science."
Verily these words from Virchow's lips sound like the bitterest irony;
for was not Lorenz Oken one of the foremost and most zealous champions
of that monistic doctrine of development against which Rudolf Virchow
at this day is most violently striving? Did not Oken himself proceed
farther in the construction of bold hypotheses and comprehensive
theories than any supporter of the doctrine of evolution at the
present time? Is not Oken justly considered as the one typical
representative of that older period of natural philosophy who rose to
much higher and bolder flights of fancy, and left the solid ground of
facts much farther behind him than any tyro of the new philosophy? And
this makes the irony seem all the greater with which Virchow at the
beginning of his address glorifies Oken the free teacher, as a martyr
to the freedom of science, and at the end of it insists that this
freedom applies only to inquiry and not to teaching, and that the
master must teach no problem, no theory, no hypothesis.

While this unheard-of demand sets Virchow's views of teaching in the
most extraordinary light, and while every unprejudiced and experienced
teacher must most emphatically protest against this strait-waistcoat
for instruction, he will feel no less bound to resist Virchow's other
strange demand, that every ascertained truth shall forthwith be taught
in all schools, down to the elementary schools. I myself, in my Munich
address, sought the instructional value of our monistic evolution
theory above all in the genetic method, in the inquiry, that is to
say, for the effective causes of the facts taught; and I added these
words--"How far the principles of the doctrine of universal evolution
ought to be at once introduced into our schools, and in what
succession its most important branches ought to be taught in the
different classes--cosmogony, geology, the phylogenesis of animals and
plants, and anthropology--this we must leave to practical teachers to
settle. But we believe that an extensive reform of instruction in this
direction is inevitable, and will be crowned by the fairest results."
I purposely avoided any closer discussion of this specialist
question, as I felt not even approximately capable of solving it, and
I believe, in fact, that none but skilled and experienced practical
teachers can undertake the solution of it with any success.

For Virchow these specialist difficulties seem not to exist; he
regards my reticence as a mere "postponement of the task," and he
answers in the following astonishing sentences:--"If the theory of
descent is as certain as Herr Haeckel assumes, then we must
demand--for it is a necessary consequence--that it shall be taught in
schools. How is it conceivable that a doctrine of such importance,
which must effect such a total revolution in all our mental
consciousness, which directly tends to create a new kind of religion,
should not be included in the school scheme of instruction? How is it
possible that such a--revelation, shall I say--should be in any
measure suppressed, or that the promulgation of the greatest and most
important advance which has been made in our views during the present
century should be left to the discretion of schoolmasters? Ay,
gentlemen, that would indeed be a renunciation of the hardest kind,
and practically it could never be carried out! Every schoolmaster who
assumes this doctrine for himself will involuntarily teach it, how can
it be otherwise?"

I must here be permitted to take Virchow exactly at his word. I
endorse almost all that he has said in these and the following
sentences. The only difference in our views is this, that Virchow
regards the theory of descent as an unproved and unproveable
hypothesis; I, on the contrary, as a fully established and
indispensable theory. How then will it be if the teachers of whom
Virchow speaks agree with my views, if--apart, of course, from all
special theories of descent--they, like me, consider the general
theory of descent as the indispensable basis of all biological
teaching? And that that is actually the case Virchow may easily
convince himself if he looks over the recent literature of zoology and
botany! Our whole morphological literature in particular is already so
deeply and completely penetrated by the doctrine of descent,
phylogenetic principles already prevail so universally as a certain
and indispensable instrument of inquiry, that no man for the future
would deprive himself of their help. As Oscar Schmidt justly
observes--"Perhaps ninety-nine per cent. of all living, or rather of
all working zoologists, are convinced by inductive methods of the
truth of the doctrine of descent." And Virchow with his magisterial
requirements will attain only the very reverse of what he aims at. How
often has it not been said already that science must either have
perfect freedom or else none at all? This is as true of teaching as
it is of inquiry, for the two are intrinsically and inseparably
connected. And so it is not in vain that it is written in section 152
of the German Code, and in section 20 of the Prussian Charter,
"Science and her teaching shall be free!"



Every great and comprehensive theory which affects the foundations of
human science, and which, consequently, influences the systems of
philosophy, will, in the first place, not only further our theoretical
views of the universe, but will also react on practical philosophy,
ethics, and the correlated provinces of religion and politics. In my
paper read at Munich I only briefly pointed out the happy results
which, in my opinion, the modern doctrine of evolution will entail
when the true, natural religion, founded on reason, takes the place of
the dogmatic religion of the Church, and its leading principle derives
the human sense of duty from the social instincts of animals.

The references to the social instincts which I, in common with Darwin
and many others, regard as the proper source and origin of all moral
development, appear to have afforded Virchow an opportunity in his
reply for designating the doctrine of inheritance as a "socialist
theory," and for attributing to it the most dangerous and
objectionable character which, at the present time, any political
theory can have; and these startling denunciations so soon as they
were known called forth such just indignation and such comprehensive
refutation that I might very properly pass them over here. Still we
must at least shortly examine them, in so far as they supply a further
proof that Virchow is unacquainted with the most important principles
of the development-theory of the day, and therefore is incompetent to
judge it. Moreover, Virchow, as a politician, manifestly attributed
special importance to this political application of his paper, for he
gave it the title, which otherwise would have been hardly suitable, of
"The Freedom of Science in the Modern Polity." Unfortunately he forgot
to add to this title the two words in which the special tendency of
his discourse culminates; the two pregnant words, "must cease!"

The surprising disclosures in which Virchow denounces the doctrine of
evolution, and particularly the doctrine of descent, as socialist
theories and dangerous to the community, run as follows:--"Now,
picture to yourself the theory of descent as it already exists in the
brain of a socialist. Ay, gentlemen, it may seem laughable to many,
but it is in truth very serious, and I only hope that the theory of
descent may not entail on us all the horrors which similar theories
have actually brought upon neighbouring countries. At all times this
theory, if it is logically carried out to the end, has an uncommonly
suspicious aspect, and the fact that it has gained the sympathy of
socialism has not, it is to be hoped, escaped your notice. We must
make that quite clear to ourselves."

On reading this statement, which seems extracted from the Berlin
"Kreuz-Zeitung," or the Vienna "Vaterland," I ask myself in surprise,
"What in the world has the doctrine of descent to do with socialism?"
It has already been abundantly proved on many sides, and long since,
that these two theories are about as compatible as fire and water.
Oscar Schmidt might with justice retort, "If the socialists would
think clearly they would feel that they must do all they can to choke
the doctrine of descent, for it declares with express distinctness
that socialist ideas are impracticable." And he proceeds to add, "And
why has not Virchow made the gentle doctrines of Christianity
responsible for the excesses of socialism? That would have had some
sense. His denunciation flung so mysteriously and so confidently
before the great public, as though it concerned 'a sure and attested
scientific truth,' is, at the same time, so hollow that it cannot be
brought into harmony with the dignity of science."

With all these empty accusations, as with all the empty reproaches and
groundless objections which Virchow brings against the doctrine of
evolution, he takes good care in no way to touch the kernel of the
matter. How, indeed, would it have been possible without arriving at
conclusions wholly opposed to those which he has declared? For the
theory of descent proclaims more clearly than any other scientific
theory, that that equality of individuals which socialism strives
after is an impossibility, that it stands, in fact, in irreconcilable
contradiction to the inevitable inequality of individuals which
actually and everywhere subsists. Socialism demands equal rights,
equal duties, equal possessions, equal enjoyments for every citizen
alike; the theory of descent proves, in exact opposition to this,
that the realisation of this demand is a pure impossibility, and
that in the constitutionally organised communities of men, as of
the lower animals, neither rights nor duties, neither possessions
nor enjoyments have ever been equal for all the members alike nor
ever can be. Throughout the evolutionist theory, as in its biological
branch, the theory of descent--the great law of specialisation or
differentiation--teaches us that a multiplicity of phenomena is
developed from original unity, heterogeneity from original similarity,
and the composite organism from original simplicity. The conditions of
existence are dissimilar for each individual from the beginning of its
existence; even the inherited qualities, the natural "disposition,"
are more or less unlike; how, then, can the problems of life and
their solution be alike for all? The more highly political life is
organised, the more prominent is the great principle of the division
of labour, and the more requisite it becomes for the lasting security
of the whole state that its members should be variously distributed in
the manifold tasks of life; and as the work to be performed by
different individuals is of the most various kind, as well as the
corresponding outlay of strength, skill, property, &c., the reward of
the work must naturally be also extremely various. These are such
simple and tangible facts that one would suppose that every reasonable
and unprejudiced politician would recommend the theory of descent, and
the evolution hypothesis in general, as the best antidote to the
fathomless absurdity of extravagant socialist levelling.

Besides, Darwinism, the theory of natural selection--which Virchow
aimed at in his denunciation, much more especially than at
transformation, the theory of descent--which is often confounded with
it--Darwinism, I say, is anything rather than socialist! If this
English hypothesis is to be compared to any definite political
tendency--as is, no doubt, possible--that tendency can only be
aristocratic, certainly not democratic, and least of all socialist.
The theory of selection teaches that in human life, as in animal and
plant life everywhere, and at all times, only a small and chosen
minority can exist and flourish, while the enormous majority starve
and perish miserably and more or less prematurely. The germs of every
species of animal and plant and the young individuals which spring
from them are innumerable, while the number of those fortunate
individuals which develop to maturity and actually reach their
hardly-won life's goal is out of all proportion trifling. The cruel
and merciless struggle for existence which rages throughout all living
nature, and in the course of nature _must_ rage, this unceasing and
inexorable competition of all living creatures, is an incontestable
fact; only the picked minority of the qualified "fittest" is in a
position to resist it successfully, while the great majority of the
competitors must necessarily perish miserably. We may profoundly
lament this tragical state of things, but we can neither controvert it
nor alter it. "Many are called but few are chosen." The selection, the
picking out of these "chosen ones," is inevitably connected with the
arrest and destruction of the remaining majority. Another English
naturalist, therefore, designates the kernel of Darwinism very frankly
as the "survival of the fittest," as the "victory of the best." At any
rate, this principle of selection is nothing less than democratic, on
the contrary, it is aristocratic in the strictest sense of the word.
If, therefore, Darwinism, logically carried out, has, according to
Virchow, "an uncommonly suspicious aspect," this can only be found in
the idea that it offers a helping hand to the efforts of the
aristocrats. But how the socialism of the day can find any
encouragement in these efforts, and how the horrors of the Paris
Commune can be traced to them, is to me, I must frankly confess,
absolutely incomprehensible.

Moreover, we must not omit this opportunity of pointing out how
dangerous such a direct and unqualified transfer of the theories of
natural science to the domain of practical politics must be. The
highly elaborate conditions of our modern civilised life require from
the practical politician such circumspect and impartial consideration,
such thorough historical training and powers of critical comparison,
that he will not venture to make such an application of a "natural
law" to the practice of civilised life, but with the greatest caution
and reserve. How, then, is it possible that Virchow, the experienced
and skilled politician, who, above all things, preaches caution and
reserve in theory, suddenly makes just such an application of
transformation and Darwinism--an application so radically perverse
that it actually flies in the face of the fundamental ideas of these
doctrines? I myself am nothing less than a politician. In direct
contrast with Virchow, I lack alike the gift and the training for it,
as well as taste and vocation. Hence I neither shall play any
political part in the future, nor have I hitherto made any attempt of
the kind. Though here and there I have occasionally uttered a
political opinion, or have made a political application of some theory
of natural science, these subjective opinions have no objective value.
In point of fact I have by so doing overstepped the limits of my
competence, just as Virchow has by going into questions of zoology and
particularly that of the transformation of apes: I am a layman in
political practice, as Virchow is in the province of zoological
hypothesis. Moreover, such success as Virchow has attained during the
twenty years of his painful, wearisome, and exhausting activity as a
politician does not, in truth, make me pine for such laurels.

But this at least I, as a theoretical naturalist, may demand of
practical politicians, that in utilising our theories for political
ends they should first make themselves exactly acquainted with them;
they then, for the future, would forbear drawing conclusions from
them, the very opposite to those which ought reasonably to be
inferred. Misunderstandings would never thus be wholly avoided,
it is true, but what doctrine is universally secure against
misunderstanding? And from what theory, however sound and true, may
not the most unsound and frantic inferences be drawn?

Nothing, perhaps, shows so plainly as the history of Christianity how
little theory and practice harmonise in human life; how little pains
are taken, even by those whose calling it is to uphold established
doctrines, to apply their natural consequences to practical life. The
Christian religion, no doubt, as well as the Buddhist, when stripped
of all dogmatic and fabulous nonsense, contains an admirable human
kernel, and precisely that human portion of Christian teaching--in the
best sense social-democratic--which preaches the equality of all men
before God, the loving of your neighbour as yourself, love in general
in the noblest sense, a fellow-feeling with the poor and wretched, and
so forth--precisely, those truly human sides of the Christian doctrine
are so natural, so noble, so pure, that we unhesitatingly adopt them
into the moral doctrine of our monistic natural religion. Nay, the
social instincts of the higher animals on which we found this religion
(for instance the marvellous sense of duty of ants, &c.) are in this
best sense strictly Christian.

And what--we may ask--what have the professed supporters, the "learned
divines" of this religion of love done? Their deeds are written in
letters of blood in the history of the civilisation of mankind during
the last 1800 years. All else that differing church-religions have
accomplished for the forcible extension of their doctrines and for the
extirpation of heretics of other creeds, all that the Jews have been
guilty of towards the heathen, the Roman emperors towards the
Christians, the Mohammedans towards Christians and Jews alike--all
this is outdone by the hecatombs of human victims which Christianity
has demanded for the spread of her doctrines. And these were
Christians against Christians--orthodox Christians against heterodox
Christians! think only of the Inquisition in the Middle Ages, of the
inconceivable and inhuman barbarities committed by the "most Christian
kings" of Spain, by their worthy colleagues in Frankfort, in Italy,
and elsewhere. Hundreds of thousands then died that most horrible
death by fire, simply because they would not bend their reason to pass
under the yoke of the grossest superstition, and because their loyalty
to their convictions forbade them to deny the natural truth that they
clearly discerned. There are no deeds more hideous, base, and inhuman
than those that at that time were committed--nay, are still
committed--in the name and on account of "true Christianity."

And finally, how do matters stand with regard to the morality of the
priests who announce themselves as the ministers of God's Word, and
whose duty is therefore above all others to carry out the saving
doctrines of Christianity in their own lives? The long, unbroken, and
horrible series of crimes of every kind which is offered by the
history of the Roman Popes is the best answer to this question. And
just as these "Vicars of God on earth" did, so did their subordinates
and accomplices, so, too, have the orthodox priests of other sects
done; never failing to set the practice of their own course of life in
the strongest possible contrast to those noble doctrines of Christian
love which were constantly on their lips.

And as with Christianity so it is with every other religious and moral
doctrine which ought to have proved its power in the wide domain of
practical philosophy, in the education of youth, in the civilisation
of nations. The theoretic kernel of this doctrine may always and
everywhere stand in the most glaring contradiction to its practical
working-out, testifying to the endless inconsistency of human nature:
but what can all this matter to the scientific inquirer? His sole and
only task is to seek for truth and to teach what he has discerned to
be the truth, indifferent as to what consequences the various parties
of state or church may happen to draw from it.



The dangerous attempt which Virchow made in Munich against the
freedom of science is not the first of its kind. On the contrary,
five years before, it experienced a similar attack which is most
intimately connected with this later one, so that, in conclusion,
we must here add a few words on the subject. Undoubtedly the famous
"Ignorabimus-speech" of Du Bois-Reymond, which he delivered in 1872 at
the forty-fifth meeting of German naturalists and physicians in
Leipzig, forms only the first portion of that same crusade against the
freedom of science of which Virchow's "Restringamur speech" of 1877,
at the fiftieth meeting of the same society, forms the second part.

That brilliant and powerful essay by Du Bois-Reymond "on the
Limitation of Natural Knowledge" has already been discussed so often,
and from such different sides, that it might seem superfluous to say
another word about it. It seems to me, nevertheless, that by most
people the centre-of-gravity of its contents was overlooked in
admiration of the brilliant accessories of the essay. Indeed this
frequently happens with Du Bois-Reymond's articles, for he knows too
well how to conceal the weakness of his argument and evidence, and the
shallowness of his thought, by striking images and flowery metaphors,
and by all the phraseology of rhetoric in which the versatile French
nature is so superior to our sober German one. It is all the more
important that we should not let ourselves be dazzled by these
seductive tricks, and particularly by adduced facts which bear upon
the most important and fundamental questions of human science, but
that we should extract the hard kernel from the savoury and fragrant
fruit. In the preface to my "Evolution of Man," and in the notes 22
and 23 of my Munich address, I have already incidentally alluded to
the chief weaknesses of the "Ignorabimus-speech;" but I must here
return somewhat more fully to the subject.

There are, as is well known, two problems which Du Bois-Reymond
propounds as the impassable boundary of human knowledge of nature;
limits which indeed the human mind is not only incapable of passing at
the present stage of its development, but which it never can be
capable of passing in any more advanced stage. The first problem is
the nature and connection of matter and force; the second is human
consciousness. Now, first of all, as has already been said in the
preface to the "Evolution of Man," we must raise a decided protest
against the air of infallibility with which Du Bois-Reymond pronounces
that these two problems are insoluble, not only at the present time
but to all futurity. The power of development inherent in science and
knowledge is hereby simply swept away with a word. Almost every great
and difficult problem of knowledge seems to most or all contemporary
thinkers insoluble, and every path to the solution of it seems closed,
till at last the bold genius appears whose clear sight detects the
right path which till then was hidden, and which leads to the required
knowledge. We need only call to mind our present doctrine of
evolution. The problem of creation--the question as to the origin of
animal and vegetable species--was universally looked upon as
transcendental and perfectly insoluble, till the genius of Lamarck
established the principles of the theory of descent in his admirable
"Philosophie Zoologique" in 1809. Nay, even then most--and among them
the most distinguished--biologists thought the problem of creation a
quite insoluble mystery, and Darwin was the first to solve it, fifty
years later, by his theory of selection in 1859. Hence we venture to
assert that there is no scientific problem of which we may dare to say
that the mind of man will never solve it even in the remotest future.
Well does Darwin say, in the introduction to his "Descent of Man,"
"Ignorance more frequently begets confidence than does knowledge: it
is those who know little and not those who know much who so positively
assert that this or that problem will never be solved by science." As
far as concerns the two separate limits which Du Bois-Reymond fixes
for human knowledge, in my opinion they are undoubtedly identical. The
problem of the origin and nature of consciousness is only a special
case of the general problem of the connection of matter and force. Du
Bois-Reymond himself indicates that this is possible at the close of
his paper; for he says, "Finally, the question arises whether the two
limitations to our natural knowledge may not perhaps be identical;
that is to say, whether if we could conceive of the true essence of
matter and force, we should not also understand how the substance
which lies at their root can, under certain given conditions, feel,
desire, and think. This conception is, no doubt, the simplest, and
according to admitted principles of inquiry it is to be preferred to
that other which it confutes, and according to which, as has been
said, the world appears doubly incomprehensible. But it is in the very
nature of things that we cannot on this point come to any clear
conclusion, and all further words on the subject are idle--and so,

The light way in which Du Bois-Reymond here passes over the most
important part of his subject is truly surprising; as if it were
ultimately indifferent whether we have before us one single insoluble
fundamental problem or two quite different ones; and as if mature
reflection did not lead to the conviction that, in fact, the second
problem is only a special case of the first general problem. I, for my
part, cannot conceive of them in any other relation; I think, too,
that all further words are by no means superfluous, but on the
contrary conduce to a very strong conviction of the unity of the
problem. That Du Bois-Reymond also has not come to any clear
conclusion on this point lies, not alone in the "nature of things,"
but, as in Virchow's case, in the nature of the investigator himself;
in his lack of knowledge of the history of evolution, and in his
neglect of those comparative and genetic methods of study, without
which, in my opinion, not even an approximate solution of this highest
and most difficult question is to be looked for.

Nothing appears to me to be of more importance for the mechanical
explanation of consciousness than the comparative consideration of its
development. We know that a new-born child has no consciousness, but
that it is slowly and gradually acquired and developed. We perceive
for ourselves how unconscious actions become conscious, and _vice
versa_. Innumerable actions which at first are troublesome and have
to be learnt with consciousness and reflection--as for instance
walking, swimming, singing, and so forth--become unconscious only by
repetition, practice, and the habit of using the organs. On the
contrary, unconscious actions become conscious as soon as we direct
our attention to them or our self-observation is attracted to them; as
for instance when we miss a step in going up stairs or touch a wrong
note on the piano; and beyond a doubt, conscious and unconscious
actions pass into each other without any distinct line of demarcation.
Finally, we see no less plainly by a comparative consideration of the
soul-life of animals, that their consciousness is slowly, gradually,
and serially developed, and that a long unbroken series of steps leads
from unconscious to conscious existence. From these comparative and
genetic experiences we may draw the conclusion that consciousness,
like sensation and volition, like all the other soul-activities, is a
function of the organism, a mechanical activity of the cells; and, as
such, is referable to chemical and physical processes. Hence, if we
were in a position to understand force as a necessary function of
matter, we could explain consciousness, as well as the soul in
general, as a necessary function of certain cells.

How little Du Bois-Reymond is acquainted with the facts of comparative
and genetic psychology, nothing shows more strikingly than the
following astounding proposition in the "Ignorabimus-speech:"--"Where
the material conditions for psychical activity, in the form of a
nervous system, are wanting, as in plants, the naturalist cannot
recognise a soul-life, and, on this point, he but seldom meets with
contradiction." Begging your pardon! Every naturalist who is familiar
with the comparative morphology and physiology of the lower animals
will here put in a decided contradiction, for he can no more refuse to
admit the undoubted sensation and voluntary motion of the one-celled
Infusoria than of the many-celled hydroid polyps. The body of the true
Infusoria (Ciliata, Acineta, &c.), and many other Protista, remain
throughout life one single cell, and, nevertheless, this cell is as
fully furnished with all the most important attributes of the soul,
with sensation and volition, as any one of the higher animals with a
nervous system. The same obtains of the Hydra and the related hydroid
polyps, in which the neuro-muscular cells, or other distributed cells
of the outer germ-layer, fulfil the soul-functions. But as these
cells, besides this, exercise motor and other functions as well, we
cannot as yet designate them as nerve-cells, at any rate there can be
no idea of a special nervous-system. The characteristic soul-organs of
the higher animals, which we include under the conception of a
nervous-system, in fact originated by the division of labour of the
cells out of those neutral cell-groups in their lower-typed ancestors.

In the great Soul-question Du Bois-Reymond, like Virchow, still keeps
his position on the standpoint of neural-psychology, according to
which no personal soul-life is conceivable without a nervous system.
We look upon this standpoint as left far behind, and set up in
opposition to it Cellular-psychology, the doctrine that every animal
cell has a soul; that is to say, that its protoplasm is endowed with
sensation and motion. In the one-celled Infusoria, which are so highly
sensitive and have such an energetic will, this conception will be
clear without any farther explanation. But we cannot refuse to allow
that plant-cells as well as animal-cells have psychic functions, since
we know that the phenomena of irritability, and of "automatic motion,"
are the universal attributes of all protoplasm. No doubt the specific
mechanism, the cause of motion, in the irritable Mimosa and other
"sensitive" plants, is quite different from the muscular motions of
animals; but these, like those, are only specifically different forms
of development of the "cell-soul," and both proceed from the
"mechanical energy of the protoplasm." The sensibility of the
irritable protoplasm is the same in the vegetable-cell of the Mimosa
as in the animal-cell of the Hydra. How far Du Bois-Reymond is from
discerning this, and how deeply he is still entangled in
neuro-psychological views is shown most clearly in the astonishing
sentence which he has thought good to append to his above-quoted,
erroneous assertion. "And what could we reply to the naturalist if,
before he could agree to the assumption of a World-soul he required
that we should show him--bedded in neuroglia and nourished by warm
arterial blood--anywhere in the world a convolution of ganglionic
centres co-extensive with the psychic capacity of such a Soul" (!)

In other respects we will not deny that Du Bois-Reymond stands far
nearer to our recent evolution-theory than Virchow; nay, that from
year to year he has always pronounced more and more emphatically in
favour of the theory of descent as the one possible explanation of
morphological phenomena; indeed, Du Bois-Reymond has lately counted
himself as one of those naturalists who were convinced of the truth of
evolution even before Darwin! Then it is only to be wondered why so
acute and gifted an inquirer, who is certainly not lacking in
scientific ambition, left it to Charles Darwin to place the egg of
Columbus on the ring and to point out to biological science a new
method of unlimited capacity by giving the theory of descent a
definite and reliable basis!

It is clear from some remarks in his discourse bearing the title
"Darwin versus Galiani" (1876), that Du Bois-Reymond is still far
from understanding the full significance of transmutation as affording
a mechanical explanation of morphological problems. In this paper the
"History of Creation" is treated simply as a romance, and the
genealogies of phylogenesis are in his eyes "of about as much value as
the pedigrees of the Homeric heroes are in the eyes of historical
critics." Geologists may be extremely grateful for this estimate of
their science, for undoubtedly geology, as a structure of hypotheses,
is neither more nor less justifiable than phylogenesis, as I have
already pointed out in my Munich address: "Our phylogenetic hypotheses
may claim to have equal value with the universally-admitted hypotheses
of geology; the only difference is this, that the mighty structure of
hypotheses called geology is incomparably more complete, simpler, and
easier to grasp than that more youthful one called phylogenesis." But
as to the much-talked-of "genealogies," though they are nothing more
than the simplest, barest, and most superficial expression of the
hypotheses of phylogenesis, as provisional hypotheses they are just as
indispensable to specific phylogenesis as the theoretical
section-tables of the strata of the earth's crust are to geology.

If Du Bois-Reymond is so convinced of the truth of transmutation as he
has lately given himself out to be, why does not he make at least one
earnest attempt to test the interpreting power of the theory of
descent in physiology--his own most special province of inquiry? Why
does he not labour at that hitherto quite unworked-out branch,
physiogenesis, at the history of the evolution of functions, at the
ontogenesis and phylogenesis of vital processes? The one idea which
has lately been often spoken of as an important discovery of Du
Bois-Reymond's--[the idea which had already been anticipated by
Leibnitz, that the "innate ideas,"--intuitions _à priori_--have
originated by transmission from primordial experience, _i.e._,
empirical, _à posteriori_ convictions], was distinctly enunciated by
me long before Du Bois-Reymond (as he omits to mention), in 1866, in
my "General Morphology" (vol. ii. p. 446), and in 1868 in the "History
of Creation" (vol. i. p. 31, vol. ii. p. 344). If Du Bois-Reymond had
practically busied himself with these problems he would certainly have
thought a little about the development of consciousness, and not have
set down as an eternally insoluble problem, "How is it possible that
matter can think?"--a form of words, be it observed, which has about
as much sense as "how matter runs," or "how matter strikes the hours."
Surely he would have guarded himself in that case from uttering the
ponderous "Ignorabimus."

The question has been repeatedly asked why two such prominent Berlin
biologists as Virchow and Du Bois-Reymond availed themselves of the
particularly solemn occasions of the fiftieth anniversary and of the
fiftieth meeting of the German naturalists and physicians to lay lance
in rest against the progress and freedom of science. The eager
approbation which they both promptly met with from the party of the
clergy and of all other enemies of free thought--Virchow, indeed, in
much greater measure than Du Bois-Reymond--appears to justify this
inquiry. I believe I can contribute something towards answering it,
and as I am not fettered by any reverence for the Berlin tribunal of
science or by any anxiety as to vexing influential Berlin connections,
as most of my colleagues are who think as I do, I do not hesitate,
here as elsewhere, to express my honest conviction in the freest and
frankest manner, not troubling myself about the wrath which may be
roused in many actual--and not actual--officials in Berlin at this
exposition of the unvarnished truth.

The primary cause of their "misunderstanding," and the best excuse
that can be offered for it, in Virchow and Du Bois-Reymond alike, lies
in their unacquaintance with the advance of modern morphology. As has
been repeatedly stated, no natural science is so directly to be
referred to the doctrine of evolution--and more particularly to the
theory of descent--as morphology. It is because we morphologists can
neither explain nor comprehend all the manifold and infinitely complex
form-phenomena of the animal and plant worlds without this theory,
because to us transmutation contains the only possible, rational
explanation of organic types, that we all regard it as the
indispensable basis of the scientific doctrine of form, and as
demanding no further proofs of its certainty than those which now lie
in abundance before us.

Du Bois-Reymond, and still more Virchow, ignore these proofs, because
they are to a great extent ignorant alike of the inquiries and
results, of the methods and the aims of our modern morphology, and
this ignorance may be accounted for partly by the one-sided direction
which their biological studies have taken, partly by the fact that
there are few universities where the study of morphology is so
behindhand as at the University of Berlin. Fully twenty years have now
elapsed since the great Johannes Müller died, the last naturalist who
could command all the departments of biology. The three great
provinces of science which had been reunited into a triune kingdom
under his powerful sceptre, were then divided among three professors'
chairs: Du Bois-Reymond took that of physiology, Virchow, theoretical
pathology (pathological anatomy and physiology), and the third, and
most important chair, that of morphology (human and comparative
anatomy, including the history of evolution) fell to Boguslaus
Reichert. This choice was, as is now universally admitted, an
incomprehensible mistake. Instead of calling Carl Gegenbaur, or Max
Schultze, or some one else of youthful capacity and vigour to the
chair of morphology--a science which is the first foundation of
zoology as well as of medicine--in Reichert they selected an elderly
school anatomist cramped by strong old-fashioned notions, who had done
some good and useful specialist work, but whose general views had
developed all awry, and who for the unexampled obscurity of his
conceptions and the confusion of his ideas, was outdone by none save
only Adolf Bastian. For twenty years this man has represented animal
morphology in the second university of Germany, and in these twenty
years hardly any work worth mentioning has been done there in the
whole of this vast department--neither by the master nor by his
pupils. We have only to compare the many worthless anatomical
productions of Berlin during these two decades (for instance, the
recent confused work by Fritsch on the brain of fishes) with the rich
mine of invaluable work produced during the preceding twenty years by
Johannes Müller and his crowd of disciples.

But, as if this were not enough, Reichert took advantage of his
influential position to hinder as far as possible all scientific study
of morphology. For example, he, with the co-operation of his
colleagues, carried through that pretended "reform" of medical
examination which puts the so-called _Tentamen physicum_ in the place
of the _philosophicum_; philosophy was entirely eliminated. Zoology
and botany, which for centuries have been very justly regarded as the
indispensable foundation of all instruction in natural science for the
young medical student, disappeared from the curriculum. Only, as if in
scorn of these sciences, in each examination a small place was
reserved for comparative anatomy--for that most difficult and
philosophical part of animal morphology which cannot be at all
understood without some previous knowledge of the other branches of
zoology. And yet comparative anatomy and the history of development
are the indispensable preliminary steps to a true scientific
comprehension of human anatomy, that most essential foundation of all
medical knowledge. Without the vivifying idea of development, mere
anatomical knowledge is an empty and lifeless cramming of the memory.

In the place of morphology, thus degraded from its office, a detailed
study of physiology was introduced, but always in a one-sided
direction. Now these two great branches of biology, which are equally
important and have an equal claim on our attention, are so dependent
the one on the other, that a real scientific understanding of organic
life can never be obtained without due relative study of both. The
masterly and incomparable teaching of Johannes Müller owed a great
part of its captivating charm to his equitable regard for morphology
and physiology, as well as to his comprehensive treatment, from the
broadest point of view, of the enormous mass of details to be dealt
with. I therefore have not the smallest doubt that the morphological
training of medical students, as at present conducted at Berlin under
the influence of Reichert and his colleagues, is as far behind that of
Müller's day, twenty or thirty years ago, in all general comprehension
of the typical organism, as it is in advance of it in specialist

In medical, as in all other scientific learning, the highest aim does
not consist in seeking to accumulate a vast chaotic mass of isolated
items of knowledge, but in a general comprehension of the science, its
aims and problems. The teacher should, above everything, guide the
pupil to this general knowledge, and then it will be easy to him, by
the aid of proper methods, to acquire mastery in each individual and
special branch. Thus in medicine, as in every other science, he is not
the best qualified who, on Bastian's method, has loaded his memory
with a confused mass of undigested facts, and has flung them all
together into his brain without any order; but, on the contrary, he
who has practically digested a considerable number of the most
important facts, and has critically co-ordinated them to a harmonious
whole. It is precisely under this aspect that transmutation is of such
inestimable value to morphology; it enables us to rise from the bare
empirical knowledge of numberless isolated facts to a philosophical
conception of their efficient causes.

The aversion and contempt which the theories of descent and selection
have met with at Berlin, more than in any other place, is in great
measure to be explained by the circumstance that, during the last two
decades, morphological studies have been more neglected in that
university than any others. In no other city of Germany has evolution
in general, as well as Darwinism in particular, been so little valued,
so utterly misunderstood, and treated with such sovereign disdain as
in Berlin. Nay, Adolf Bastian, the most zealous of all the Berlin
opponents of our doctrines, has insisted on these facts with peculiar
satisfaction. Of all the conspicuous naturalists of Berlin only one
accepted the doctrine of transmutation from the beginning with sincere
warmth and full conviction, being, indeed, persuaded of its truth even
before Darwin himself. This was the gifted botanist Alexander Braun,
who is lately dead--a morphologist who was equally distinguished by
the extent of his comprehensive knowledge of details, as by his
philosophical mastery over them. His firm conviction of the truth of
the theory of descent is all the more remarkable because he was at the
same time a spotless character, a pious Christian in the best sense of
the word, and an extremely conservative politician; a striking example
that these convictions can dwell side by side with the principles of
the recent doctrines of evolution in one and the same person. But in
comparison with the powerful influence of the rest of the Berlin
naturalists who, for the most part, are decided opponents of
transmutation, and who have only lately--a few of them, to follow the
fashion--become converts to it, a man like Alexander Braun could have
no effect in procuring that it should be taught.

However, this is not the first time that this very Berlin society of
learned men has set itself with remarkable firmness against the most
important advances of science. Virchow's former colleague, the
deceased Stahl, with a similar purpose and with great success,
preached this principle: "Science must turn back again." Just as at
the present day the Berlin biologists have opposed the most obstinate
and pertinacious resistance to the greatest scientific stride of this
century, so did it happen in former times with regard to other
doctrines of progress. We have only to recall Caspar Friedrich Wolff,
the great inquirer, who in 1759 first detected the nature of the
individual processes of development in the animal ovum, and founded
on it his observations in his "Theoria Generationes," which marked
an epoch in biological science. The Berlin savants, full of the
prevailing prejudices, so contrived at that time that Wolff never once
could obtain the permission which he craved, to lecture publicly, and
in consequence found himself compelled to retire to St. Petersburg for
the sake of peace. And yet in that instance there was no question
of a "theory" properly so-called. For the fundamental theory of
generation--the "theory of epigenesis"--as propounded by Wolff was
nothing more than a simple, general exposition of embryological facts
which he had been the first to recognise, and of whose truth every one
might convince himself by direct observation. In spite of this, for
another half century, the predominant error of the "Preformation-theory"
continued to be universally accepted--the ludicrous and nonsensical
doctrine, supported by the authority of Haller, that all the successive
generations of animals exist preconceived and enclosed one within the
other, and that no individual development ever takes place! _Nulla est
epigenesis!_ (Compare my "Evolution of Man," vol. i. p. 31.)

But it would appear that it is the fate of that most interesting of
all sciences, the history of evolution, to find its most important
steps and its greatest discoveries met by the firmest and most
persistent opposition. For while Wolff's fundamental theory of
epigenesis, which was promulgated in 1759, was not recognised until
1812, Lamarck's theory of descent, founded in 1809, had to wait fully
fifty years before Darwin, in 1859, showed it to be the greatest
acquisition of modern science; and during that period, in spite of all
the progress made in empirical science, how persistently this most
comprehensive of all biological theories was combated. We need only
recollect how, in 1830, the celebrated George Cuvier silenced its most
eloquent supporter, Geoffroy St. Hilaire, in the midst of the Paris
Academy, and how almost at the same time its founder, the great
Lamarck, ended his life in blindness, misery and want, while his
opponent Cuvier was enjoying the highest honours and the greatest
splendour. And yet we know now that the despised and contemned Lamarck
and Geoffroy had already grasped truths of the highest significance,
while Cuvier's much-admired and universally-accepted theory of
creation is now on all hands neglected as an absurd and untenable
delusion. But as neither Haller as against Wolff, nor Cuvier as
against Lamarck, could permanently hinder the progress of free
inquiry, neither will Virchow succeed in turning back the course of
Darwin's admirable achievement; no, not even when he is supported by
the discourses of his friend Bastian.

While we cannot but earnestly lament Virchow's inimical attitude in
this great struggle for truth, we must not overlook the effects of his
well-founded authority in a yet wider sphere. For instance, the
hostile attitude which the greater part of the Berlin press
persistently maintains towards the doctrine of development
(particularly the Liberal "National-Zeitung") is to be referred to the
influence of his authority. But much as this reactionary vein, in this
and in other intelligent circles at Berlin, must be regretted on the
one hand, on the other we must observe that by this evil we have been
preserved from a far greater one. This greater evil--the greatest, in
fact, which German science could have to encounter--would be the
monopoly of knowledge at Berlin; a Centralisation of Science. The
injurious fruits of this system of centralisation in France, for
instance, the continual deterioration of French science through the
Parisian "Monopoly of Knowledge," and its steady decline during half a
century from the sublimest heights--these are all well known. From
such a centralisation of German science--which would be especially
dangerous if it occurred in the capital, Berlin--we may hope to be
preserved; in the first place by the manifold differences and the
many-sided individuality of the German national spirit, the
much-abused German provincialism (Particularismus). While these
provincial modes of thought can never have any permanent political
value, nor be productive of a desirable form of government, it is
beyond a doubt that their outcome has been fruitful and happy for
German science. For it owes its splendid pre-eminence over that of
other countries precisely to the many centres of culture which were
offered by those numerous petty capitals of the minor German States
which strove to outdo each other in eager emulation. It is to be hoped
that this happy decentralisation of science in our politically united
fatherland may continue to subsist!

And next to this centrifugal tendency of our German national mind
nothing will so greatly contribute to it as a vigorous opposition to
the free advance of science, such as is just now declaring itself in
the metropolis. For by just so much as Berlin is dragged back by it in
the mighty onward stream of free intellectual movement, by so much
will it see itself outstripped by the other seats of culture in
Germany, which follow the stream with enthusiasm, or at least without
resistance. If Emil du Bois-Reymond raises the cry of "Ignorabimus,"
and Rudolf Virchow his still more audacious one of "Restringamur," as
the watchwords of science, then, from Jena, let the shout be raised
and echoed from a hundred other universities--"Impavidi progrediamur!"


       *       *       *       *       *


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History in Chicago High-School. 8vo. Cloth. Price, $2.00.

books of Cæsar's Gallic War, Sallust's Catiline, and eight Orations of
Cicero. With Notes, Illustrations, a Map of Gaul, and a Special
Dictionary. 12mo. Cloth. Price, $1.75.

HARKNESS'S SALLUST'S CATILINE, with Notes and a Special Vocabulary.
12mo. Cloth. Price, $1.15.

THE LATIN SPEAKER. Easy Dialogues, and other Selections for Memorizing
and Declaiming in the Latin Language. By FRANK SEWALL, A. M. 12mo.
Cloth. Price, $1.00.

       *       *       *       *       *

New Volume of "The International Scientific Series."





1 _vol._, 12_mo. Cloth, price_, $1.75.

"In the present work I have surveyed the Teaching Art, as far as
possible, from a scientific point of view; which means, among other
things, that the maxims of ordinary experience are tested and amended by
bringing them under the best ascertained laws of the mind."--_From

"Dr. Bain's _renovated curriculum_ is certainly extensive enough, even
if it omits Greek and Latin. According to this, higher education should
embrace--first, science; second, the humanities, including history and
the social science, and some portions of the universal literature; and,
third, English composition and literature."--_New York Evening Express._

"The work should become a text-book for teachers, not to be followed
servilely or thoughtlessly, but used for its suggestiveness."--_Boston

"Professor Bain is not a novice in this field. His work is admirable in
many respects for teacher, parent, and pupil."--_Philadelphia North

"A work of great value to all teachers who study it
intelligently."--Boston Advertiser.__

"At once speculative and practical, entering largely into the philosophy
of teaching, and manfully handling facts."--_Philadelphia Press._

       *       *       *       *       *



_18mo. Flexible cloth, 45 cents each._

I.--Edited by Professors HUXLEY, ROSCOE, and BALFOUR STEWART.


  Chemistry                    H. E. ROSCOE.
  Physics                      BALFOUR STEWART.
  Physical Geography           A. GEIKIE.
  Geology                      A. GEIKIE.
  Physiology                   M. FOSTER.
  Astronomy                    J. N. LOCKYER.
  Botany                       J. D. HOOKER.
  Logic                        W. S. JEVONS.
  Inventional Geometry         W. G. SPENCER.
  Pianoforte                   FRANKLIN TAYLOR.
  Political Economy            W. S. JEVONS.

II.--Edited by J. R. GREEN, M.A., _Examiner in the School of Modern
History at Oxford_.


  Greece                       C. A. FYFFE.
  Rome                         M. CREIGHTON.
  Europe                       E. A. FREEMAN.
  Old Greek Life               J. P. MAHAFFY.
  Roman Antiquities            A. S. WILKINS.
  Geography                    GEORGE GROVE.

III.--Edited by J. R. GREEN, M.A.


  English Grammar              R. MORRIS.
  English Literature           STOPFORD BROOKE.
  Philology                    J. PEILE.
  Classical Geography          M. F. TOZER
  Shakespeare                  E. DOWDEN.
  Studies in Bryant            J. ALDEN.
  Greek Literature             R. C. JEBB.
  English Grammar Exercises    R. MORRIS.
  Homer                        W. E. GLADSTONE.

_(Others in preparation.)_

The object of these primers is to convey information in such a manner
as to make it both intelligible and interesting to very young pupils,
and so to discipline their minds as to incline them to more systematic
after-studies. They are not only an aid to the pupil, but to the
teacher, lightening the task of each by an agreeable, easy, and
natural method of instruction. In the Science Series some simple
experiments have been devised, leading up to the chief truths of each
science. By this means the pupil's interest is excited, and the memory
is impressed so as to retain without difficulty the facts brought
under observation. The woodcuts which illustrate these primers serve
the same purpose, embellishing and explaining the text at the same

       *       *       *       *       *




    W. T. HARRIS, LL. D.,
    _Superintendent of Schools,
    St. Louis, Mo._

    A. J. RICKOFF, A. M.,
    _Superintendent of Instruction,
    Cleveland, O._

    _Instructor in Elocution,
    Yale College._

                               RETAIL PRICES.

    APPLETONS' FIRST READER        $0.25
    APPLETONS' THIRD READER          .52
    APPLETONS' FIFTH READER         1.25


These Readers, while avoiding extremes and one-sided tendencies,
combine into one harmonious whole the several results desirable to be
attained in a series of school reading-books. These include good
pictorial illustrations, a combination of the word and phonic methods,
careful grading, drill on the peculiar combinations of letters that
represent vowel-sounds, correct spelling, exercises well arranged for
the pupil's preparation by himself (so that he shall learn the great
lessons of self-help, self-dependence, the habit of application),
exercises that develop a practical command of correct forms of
expression, good literary taste, close critical power of thought, and
ability to interpret the entire meaning of the language of others.


The high rank which the authors have attained in the educational field
and their long and successful experience in practical school-work
especially fit them for the preparation of text-books that will embody
all the best elements of modern educative ideas. In the schools of St.
Louis and Cleveland, over which two of them have long presided, the
subject of reading has received more than usual attention, and with
results that have established for them a wide reputation for superior
elocutionary discipline and accomplishments. Feeling the need of a
series of reading-books harmonizing in all respects with the modes of
instruction growing out of their long tentative work, they have
carefully prepared these volumes in the belief that the special
features enumerated will commend them to practical teachers

Of Professor Bailey, Instructor of Elocution in Yale College, it is
needless to speak, for he is known throughout the Union as being
without a peer in his profession. _His methods make natural, not
mechanical readers._

       *       *       *       *       *



Natural Science and the Progress of Discovery,




With Illustrations. 12mo. Cloth, $2.00.

"During many years the author acted as secretary to Sir Charles
Lyell, and was brought in contact with many of the leading scientific
men of the day, and felt very forcibly how many important facts and
generalizations of science, which are of great value both in the
formation of character and in giving a true estimate of life and
its conditions, are totally unknown to the majority of otherwise
well-educated persons. This work has been written for this purpose,
and it is not too much to say that it will effect its
purpose."--_European Mail_.

"The volume is attractive as a book of anecdotes of men of science and
their discoveries. Its remarkable features are the sound judgment with
which the true landmarks of scientific history are selected, the
conciseness of the information conveyed, and the interest with which
the whole subject is nevertheless invested. Its style is strictly
adapted to its avowed purpose of furnishing a text-book for the use of
schools and young persons."--_London Daily News_.

"Before we had read half-a-dozen pages of this book we laid it down
with an expression of admiration of the wonderful powers of the
writer. And our opinion has increased in intensity as we have gone on,
till we have come to the conclusion that it is a book worthy of being
ranked with Whewell's 'History of the Inductive Sciences'; it is one
which should be first placed in the hands of every one who proposes to
become a student of natural science, and it would be well if it were
adopted as a standard volume in all our schools."--_Popular Science

"A most admirable little volume. It is a classified résumé of the
chief discoveries in physical science. To the young student it is a
book to open up new worlds with every chapter."--_Graphic_.

"We have nothing but praise for this interesting book. Miss Buckley
has the rare faculty of being able to write for young
people."--_London Spectator_.

"The book will be a valuable aid in the study of the elements of
natural science."--_Journal of Education_.

       *       *       *       *       *



Author of "A Short History of Natural Science," etc.


12mo Cloth, price, $1.50.

"A child's reading-book admirably adapted to the purpose intended. The
young reader is referred to nature itself rather than to books, and is
taught to observe and investigate, and not to rest satisfied with a
collection of dull definitions learned by rote and worthless to the
possessor. The present work will be found a valuable and interesting
addition to the somewhat overcrowded child's library."--_Boston

"Written in a style so simple and lucid as to be within the
comprehension of an intelligent child, and yet it will be found
entertaining to maturer minds."--_Baltimore Gazette._

"It deserves to take a permanent place in the literature of
youth."--_London Times._

"The ease of her style, the charm of her illustrations, and the
clearness with which she explains what is abstruse, are no doubt the
result of much labor; but there is nothing labored in her pages, and
the reader must be dull indeed who takes up this volume without
finding much to attract attention and to stimulate inquiry."--_Pall
Mall Gazette._

"So interesting that having once opened it we do not know how to leave
off reading."--_Saturday Review._

"We are compelled to admit that there is indeed a fairy-land of
science. This is the fairy-land upon which Miss Arabella Buckley
lectured last year, and upon which she has now produced a child's
reading-book, which is most charmingly illustrated, and which is in
every way rendered especially interesting to the juvenile
reader."--_London Athenæum._

       *       *       *       *       *


In neat 12mo volumes, bound in cloth, fully illustrated. Price per
volume, $1.00.

This series of scientific books for boys, girls, and students of every
age, was designed by Prof. Alfred M. Mayer, Ph. D., at the Stevens
Institute of Technology, Hoboken, New Jersey. Every book is addressed
directly to the young student, and he is taught to construct his own
apparatus out of the cheapest and most common materials to be found.
Should the reader make all the apparatus described in the first book
of this series, he will spend only $12.40.



A Series of Simple, Entertaining, and Inexpensive Experiments in the
Phenomena of Light, for Students of every Age.



A Series of Simple, Entertaining, and Inexpensive Experiments in the
Phenomena of Sound, for the Use of Students of every Age.


Professor of Physics in the Stevens Institute of Technology; Member of
the National Academy of Sciences; of the American Philosophical
Society, Philadelphia; of the American Academy of Arts and Sciences,
Boston; of the New York Academy of Sciences; of the German
Astronomical Society; of the American Otological Society; and Honorary
Member of the New York Ophthalmological Society.


III. Vision and the Nature of Light.

IV. Electricity and Magnetism.

V. Heat.

VI. Mechanics.

VII. Chemistry.

VIII. The Art of experimenting with Cheap and Simple Instruments.

       *       *       *       *       *


_A Series of Simple, Entertaining, and Inexpensive Experiments in the
Phenomena of Light, for the Use of Students of Every Age._



"Professor Mayer has invented a series of experiments in Light which
are described by Mr. Barnard. Nothing is more necessary for
sound-teaching than experiments made by the pupil, and this book, by
considering the difficulty of costly apparatus, has rendered an
important service to teacher and student alike. It deals with the
sources of light, reflection, refraction, and decomposition of light.
The experiments are extremely simple and well suited to young
people."--_Westminster Review._

"This work describes, in simple language, a number of experiments
illustrating the principal properties of light, by means of a beam of
sunlight admitted into a dark room, and various contrivances. The
experiments are highly ingenious, and the young student can not fail
to learn a great deal from the book. As an example of the effective
experimental method employed, we may specially mention the device for
illustrating the refraction of light. This book is specially designed
'to give to every teacher and scholar the knowledge of the art of
experimenting.'"--_The Quarterly Journal of Science_ (London).

"A singularly excellent little hand-book for the use of teachers,
parents, and children. The book is admirable both in design and
execution. The experiments for which it provides are so simple that an
intelligent boy or girl can easily make them, and so beautiful and
interesting that even the youngest children must enjoy the exhibition.
The experiments here described are abundantly worth all that they cost
in money and time in any family where there are boys and girls to be
entertained."--_New York Evening Post._

"The experiments are capitally selected, and equally as well
described. The book is conspicuously free from the multiplicity of
confusing directions with which works of the kind too often abound.
There is an abundance of excellent illustrations."--_New York
Scientific American._

"The experiments are for the most part new, and have the merit of
combining precision in the methods with extreme simplicity and
elegance of design. The value of the book is further enhanced by the
numerous carefully-drawn cuts, which add greatly to its
beauty."--_American Journal of Science and Arts._

       *       *       *       *       *


_A Series of Simple, Entertaining, and Inexpensive Experiments in the
Phenomena of Sound, for the Use of Students of Every Age._


Professor of Physics in the Stevens Institute of Technology; Member of
the National Academy of Sciences, etc.

Uniform with "LIGHT," first volume of the Series.

Neat 12mo volume, fully illustrated. Cloth, price, $1.00.

"It would be difficult to find a better example of a series which is
excellent throughout. This little work is accurate in detail, popular
in style, and lucid in arrangement. Every statement is accompanied
with ample illustrations. We can heartily recommend it, either as an
introduction to the subject or as a satisfactory manual for those who
have no time for perusing a larger work. It contains an excellent
description, with diagrams, of Faber's Talking Machine and of Edison's
Talking Phonograph, which can not fail to be interesting to any reader
who takes an interest in the marvelous progress of natural
science."--_British Quarterly._

"The style of the book is very clear, and the experiments interesting.
It can not fail to have an important educational influence."--_Westminster

"It would really be difficult to exaggerate the merit, in the sense of
consummate adaptation to its modest end, of this little treatise on
'Sound.' It teaches the youthful student how to make experiments for
himself, without the help of a trained operator, and at very little
expense. These hand-books of Professor Mayer should be in the hands of
every teacher of the young."--_New York Sun._

"An admirably clear and interesting collection of experiments,
described with just the right amount of abstract information and no
more, and placed in progressive order. The recent inventions of the
phonograph and microphone lend an extraordinary interest to this whole
field of experiment, which makes Professor Mayer's manual especially
opportune."--_Boston Courier._

       *       *       *       *       *

The Works of Professor E. L. YOUMANS, M. D.

_Class-book of Chemistry._

New edition. 12mo. Cloth, $1.50.

_The Hand-book of Household Science._

A Popular Account of Heat, Light, Air, Aliment, and Cleansing, in
their Scientific Principles and Domestic Applications. 12mo.
Illustrated. Cloth, $1.75.

_The Culture demanded by Modern Life._

A Series of Addresses and Arguments on the Claims of Scientific
Education. Edited, with an Introduction on Mental Discipline in
Education. 1 vol., 12mo. Cloth, $2.00.

_Correlation and Conservation of Forces._

A Series of Expositions by Professor Grove, Professor Helmholtz, Dr.
Mayer, Dr. Faraday, Professor Liebig, and Dr. Carpenter. Edited, with
an Introduction and Brief Biographical Notices of the Chief Promoters
of the New Views, by EDWARD L. YOUMANS, M. D. 1 vol., 12mo. Cloth,

       *       *       *       *       *

_The Popular Science Monthly._

Conducted by E. L. and W. J. YOUMANS.

Containing instructive and interesting articles and abstracts of
articles, original, selected, and illustrated, from the pens of the
leading scientific men of different countries;

Accounts of important scientific discoveries;

The application of science to the practical arts;

The latest views put forth concerning natural phenomena, by savants of
the highest authority.

TERMS: Five dollars per annum; or fifty cents per number. A Club of
five will be sent to any address for $20.00 per annum.

The volumes begin May and November of each year. Subscriptions may
begin at any time.

$7.00 per annum, postage prepaid.

       *       *       *       *       *

_A New and Valuable Work for the Practical Mechanic and Engineer._





Edited by PARK BENJAMIN, Ph. D.


  T. A. EDISON, PH. D.
  LIEUT. A. A. BOYD, U. S. N.
  H. A. MOTT, JR., PH. D.
  W. H. PAYNE, C. E.

not a revision of the former Dictionary of Mechanics of 1850. It aims
to present the best and latest American practice in the mechanical
arts, and to compare the same with that of other nations. It also
exhibits the extent to which American invention and discovery have
contributed to the world's progress during the last quarter century.
Its production is deemed timely in view of the existing popular
interest in the labors of the mechanic and inventor which has been
awakened by the great International Expositions of the last decade,
and by the wonderful discoveries made by American inventors during the
past three years.

The CONTRIBUTORS whose names are given above number many of the most
eminent American mechanical experts and engineers. Several of their
contributions contain the results of original research and thought,
never before published. Their efforts have in all cases tended to
simplify the subjects treated, to avoid technicalities, and so to
render all that is presented easily understood by the general reader
as well as by the mechanical student. Examples are appended to all
rules, explanations to all tables, and in such matters as the uses of
tools and management of machines the instructions are unusually minute
and accurate.

In semi-monthly Parts, 50 cents each.

Subscriptions received only for the entire work of Twenty-four Parts.

       *       *       *       *       *


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