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FREEDOM IN SCIENCE AND
TEACHING.

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FREEDOM

IN

SCIENCE AND TEACHING.

FROM THE GEKMAN OF

ERNST HAECKEL.

WITH A PREFATORY NOTE

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

Der Teleolog.
" Welche Verehruag verdient der Weltenschopfer, der gjadig.
Als er den Korkbaum schuf, gleich aucli die Stopfel erfand."

Xenien.

NEW YORK:
D, APPLETON AND COMPANY,

549 AND 551 BROADWAY.
1879.

BOSTON COLLEGE LIBRARY
_^ gHESTIsiyT HILL, MASS^

n

PREFATORY NOTE.

In complying with the wish of the publishers of Pro-
fessor 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 contro-
versy, 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 received.

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

vi PRE FA TOR V NO TE.

of both the attack and the reply leaves me without the
inclinatioii 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 impor-
tant 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 — " Ta^^e
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

PREFA TORY NOTE. vii

abstrahere"^ 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 ; " ^ and each may adduce abundant his-
torical 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 fol-
lowed. 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 formulse and bold genera-
lisations for solid truths because of their brilliancy

1 Novum Organon, li.

2 Partis instaurationis secundse delineatio.

viii PREFATORY NOTE.

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 Yirchow, 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 obscuran-
tists 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 hap-
pened to the two women grinding at the same mill,
one has been taken and the other left. Since the pub-
lication of his famous oration, Yirchow has been received
into the bosom of orthodoxy and respectability, while
Haeckel remains an outcast !

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

PREFA TOR V NOTE. ix

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 Ger-
many ; 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 pro-
positions which they have a fair right to regard as estab-
lished 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

PRE FA TOR V NOTE.

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 indubit-
able, 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 hypo-
thetical— 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 difiicult
subject, than that which arises out of the effort to put
them forth, with fulness and precision, in language

PREFATORY NOTE. xi

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 encroach-
ment 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 " sick ent-suhjectiviren " — 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

xii PREFATORY NOTE.

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.'^

With respect to another side issue, raised by Pro-
fessor Yirchow, he appears to me to be entirely in
the wrong. He is careful to say that he has no

^ 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, be-
lieved in equivocal generation ; and, in the sense in which he uses the
word ovum, "nempe substantiam quandam corpoream vitam haben-
tem 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.

PRE FA TOR V NO TE. xiii

unwillingness to accept the descent of man from some
lower form of vertebrate life ; but, reminding ns 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 asser-
tion of Professor Virchow's appears to me to be a
typical example of the kind of incautious over-state-
ment 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 Yirchow'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 man-
kind."^ 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

^ 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.

xiv PREFATORY NOTE.

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 palseontology 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 Eqiiidce 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 Anthropidce, 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 live.

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

PRE FA TOR Y NO TE. xv

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." ^

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 Eecent and Quaternary to the Ter-
tiary mammalia appears to me to be in striking har-
mony with what we know respecting Quaternary man,
supposing man to have followed the general law of
evolution.

The only other collateral question of importance raised
by Professor Virchow is, whether the doctrine of evolu-
tion should be generally taught in schools or not. l^ow
I cannot find that Professor Virchow anywhere dis-
tinctly repudiates the doctrine ; all that he distinctly
says is that it is not proven, and that things which
1 Man's Place in Nature, p. 159.

xvi PREFA TOR V NOTE.

are not proven should not be authoritatively instilled
into the minds of young people.

If Professor Yirchow will agree to make this excel-
lent 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 imperfec-
tion of the evidence for evolution in order to express
tliat 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 ? l!^ay,
surely even Profes&or 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

PRE FA TOR V NO TE. xvii

to offer to the authoritative propagation of the pre-
posterous 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 re-
ligion 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 Yirchow so far, but for very diffe-
rent 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 know-
ledge which is needed for the critical examination of
the dogmas, whether scientific or anti-scientific, which
are presented to the adult mind. At present, educa-
tion proceeds in the reverse way ; the teacher makes
the most confident assertions on precisely those sub-

xviii PRE FA TOR V NO TE.

jects of which he knows least ; while the habit of
weighing evidence is disconraged, and the means of
forming a sound judgment are carefully withheld
from the pupil.

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 pre-
ceding 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 intro-
duction 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

PREFA TOR V NOTE. xix

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 Socialist."

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 Soci-
alists. All the greater is my regret that Professor Vir-
chow did not himself unfold the links of the hidden
bonds which unite evolution with revolution, and bind
together the community of descent with the commu-
nity of goods.

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

" Wlio 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

XX PREFA TOR V NO TE.

to the attempt to frighten sober people by the sugges-
tion that evolutionary speculations generate revolu-
tionary schemes in Socialist brains. But then the
authors of the " Eejected Addresses " were joking,
while Professor Virchow is in grim earnest ; and that
makes a great difference in the moral aspect of the
two achievements.

PREFACE.

When the address delivered by Eudolph Yircliow on
the 2 2d 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 Yirchow 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 Eolation to General Science." The
general views which Yirchow 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 pub-
lishing 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 con-

xxii PREFACE.

tention that lias declared itself between us. Eor on
one hand the doctrine of evolution which Yirchow
attacks has already so far become a sure basis of bio-
logical science and part of the most precious mental-
stock of cultivated humanity, that neither the ana-
themas of the Church nor the contradiction of the
greatest scientific authority — and such an one is Vir-
chow — 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 dis-
cussed 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 ac-
knowledge 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 assis-
tant, 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 anta-
gonist 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, never-
•theless, to come forward publicly as the "opponent of
this distinguished and highly-honoured man.

PREFACE, xxiii

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 Yirchow's scien-
tific 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 unconquer-
able aversion to the evolution theory, accused me,
in one of its hostile articles, of a virulent and un-
dignified 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

xxiv PREFACE.

that, therefore, the matter in question is not an -unjus-
tifiable 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 utili-
sation of his authority of which the pernicious conse-
quences can by no means be escaped. Friedrich von
Hellwald, in his discussion on the speeches made at
Munich, has already strikingly pointed out-^ the grave
danger that exists when just such an one as Yirchow,
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 encounter-
ing such a reaction as has not occurred for a long
time. The two insane attempts which, within a few

i Kosmos, Vol. II. p. 172.

PREFACE. XXV

weeks, have been made by Social- democracy against
tlie revered and reverend person of the German
Emperor have raised a storm of righteous indignation
of such violence that calm judgment is entirely over-
thrown, 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 free-
dom of the press and even freedom of conscience shall
be thrown into the narrowest fetters. Can this re-
action, lurking in the background, find any more
welcome support than is afforded by the mere demand
of such a man as Yirchow 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 Hodel and INTobiling^ — 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 Yirchow has at the present day as
an advanced liberal, and how he is regarded in the

9.

xxvi PREFACE.

Prussian diet as the highest practical authority, and at
the same time as the most liberal critic when educa-
tional questions are under consideration. Now it is
well known that one of the most important problems
lying before the Prussian parliament is the consider-
ation 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,
Yirchow 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 § i 5 2 of the Code of the
German Empire, say, " Science and its doctrines are
free." And Virchow's first step, according to the prin-
ciples 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 arnica 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 i8th September 1877, and left

PREFACE. xxvii

on the 19th. Virchow came to Munich only on the
20th, and delivered his speech on the 2 2d.

Bearing in mind the gratitude which I owe to Vir-
chow as my former master and friend at Wurzburg — 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).^ Vir chow's return for
this was to heap scorn and ridicule on the doctrine of
evolution in his usual manner. The critic in the
" N"ational-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 justified."

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

* Of the German.

xxviii PREFACE,

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 Yirchow insists with the utmost determina-
tion 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. Yirchow 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 ! ITo thing 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 Yirchow's purpose, as it is gene-
rally supposed to be, with regard to me, at least, he may
spare himself the trouble. Amongst us in Jena quite

PREFACE. xxix

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." ^

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

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

The Eector 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 illus-
trious head of the party of progress at Berlin. The en-
lightened 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 youth-

1 " Wer die Wahrheit kennet und saget sie frei,

Der kommt in Berlin auf die Stadt- Vogtei. "

2 *' Wer die Wahrheit kennet und saget sie nicht

Der ist fur wahr ein erbarmlicher Wicht."

XXX PREFACE.

ful 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 extend-
ing over three centuries, the little Thuringian uni-
versity 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 hier-
archical 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 linl^ed
with the history of German intellect through the

PREFACE, xxxi

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.

ERNST HAECKEL.
Jkna, June 24th, 1878.

CONTENTS.

PAOK
PREFATORY NOTE . . . , . . . . V

PREFACE xxi

CHAP.
I. DEVELOPMENT AND CREATION I

II. CERTAIN PROOFS OF THE DOCTRINE OF DESCENT . lO

III. THE SKULL THEORY AND THE APE THEORY . . 29

IV. THE CELL-SOUL AND CELLULAR PSYCHOLOGY . . 46
V. THE GENETIC AND DOGMATIC METHODS OF TEACHING 61

VL THE DOCTRINE OF DESCENT AND SOCIAL DEMOCRACY 88

VIL IGNORABIMUS ET RESTRINGAMUR . . . . '99

FREEDOM IN SCIENCE AND TEACHING.

CHAPTEE I.

DEVELOPMENT AND CREATION.

Nothing- is more helpful for the understanding of
scientific controversies, or for the clearing of con--
fused 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 inde-
pendently of each other, and in that case can only
have been created in a supernatural way, by a
miracle. Natural evolution, or supernatural creation

2 DEVELOPMENT AND CREATION.

of species — we must choose one of these two possi-
bilities, 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 sub-
ordination of these three great theories.

I. The general doctrine of development, the pro-
genesis-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

DEVELOPMENT AND CREATION. 3

we see the organic species, the multiform varieties of
animals and plants, vary under our eyes through
adaptation, while the similarity of their internal struc-
ture 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 trans-
mutation ; " 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

4 DEVELOPMENT AND CREATION.

domestication — as tlie races of domestic animals and
cultivated plants- — throngh artificial choice of breeds ;
and tlie 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

DEVELOPMENT AND CREATION. 5

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 trans-
formation— 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 migra-
tion, which acts as isolation or separation, as merely
a special mode of selection. But these differing estim-
ates of Darwinism are quite independent of the absolute

6 DEVELOPMENT AND CREA TION. .

import of tlie doctrine of descent or of transformation,
for the latter is as yet the only theory which ration-
ally explains the origin of species. If we discard it,
nothing remains but the irrational assumption of a
miracle, a supernatural creation.

In this crucial and unavoidable dilemma, Yirchow 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 unpreju-
diced 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 Darwin-
ism 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. Yirchow 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,

DEVELOPMENT AND CREATION. 7

greeted Ms Munich discourse. This " enfant terrible "
of the school — this well-nicknamed " Acting privy
counsellor of the board of confusion "^ — whose merits
in involuntarily advancing the cause of metamorphism
I have already done justice to in the preface to the
third edition of my " ISTatural History of Creation "^; —
expresses himself in the " Zeitschrift ftir Ethnologic/'
which is edited by him and Yirchow (tenth yearly
part, X. 1878, p. 66) as follows: — "At the Munich
meeting of naturalists, Yirchow 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 night-
mare 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

1 ' Wirkliche Geheime Ober-Conf usionsrath. "

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

8 DEVELOPMENT AND CREATION.

every ear is too mucli deafened by tlie 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 dens vnlt 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 soM
contributions."

Furthermore, Bastian quotes Yirchow'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 Yirchow has become a Dualist, and

DEVELOPMENT AND CREATION. 9

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 acknow-
ledging his chief standpoint in all its nakedness.
On the contrary, even now he still veils his anta-
gonism 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 Ke 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 evolu-
tion. Then what are the new proofs of the theory of
descent which Virchow demands of us ?

CHAPTER 11.

CERTAIN PROOFS OF THE DOCTRINE OF DESCENT.

All the common phenomena of Morphology and
Physiology, of Chorology and (Ekology, 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,"-^ or
"The Evolution of Man" (vol. i. p. 93).^

And where is yet farther proof of the truth of the

1 Vol. ii. , p. 334 of translation.

2 London : C. Kegan Paul & Co. 1879.

THE DOCTRINE OF DESCENT. ii

theory of descent to be found ? Neither Yirchow,
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 Yirchow
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 hear-
ing 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

12 CERTAIN EVIDENCE OF

species, the transition of a species into one or more
new varieties," is the answer.. N"ow, 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 transforma-
tion 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 repre-
sentatives of different species. Undoubtedly, these
so-called " races " and " sports " of the horse tribe dif-
fer 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 " bonse 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

THE DOCTRINE OF DESCENT. 13

varieties of pigeons. Domestic pigeons and carrier-
pigeons, tnrbits and cropper-pigeons, fantail pigeons
and owls, tumblers and pouters, trumpeters and laugh-
ing pigeons (or Indian doves), and tlie rest, are all, as
Darwin has convincingly proved, descendants of a
single wild variety, the rock-pigeon (Columba lima).
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 par-
ticular stress on the fact that these artificial species
which man has produced or created by artificial breed-
ing 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. Tor, 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.

14 CERTAIN EVIDENCE OF

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 unpre-
judiced 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 mu.st 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 ex-
periences and experiments, that two different true varie-
ties 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,

777^ DOCTRINE OF DESCENT. 15

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. 146).

For a certain proof that the conception of species
rests on a subjective abstraction and has a merely rela-
tive value — like the conception of genus, family, order,
class, &c. — no class' of animals is of so much importance
as that of the ^onges. In it the fluctuating forms
vary with such unexampled indefiniteness and varia-
bility as to make all distinction of species quite illusory
Oscar Schmidt has already pointed this out in the sili-
ceous 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 1 1 1, or 2%g,
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.
8

i6 CERTAIN EVIDENCE OF

Hence I tliink I liave here produced tlie 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 Yirchow 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. ]!^either 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, Yirchow 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 for-
ward of modern natural science without in any way

THE DOCTRINE OF DESCENT. 17

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 know-
ledge 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 abso-
lutely 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

i8 CERTAIN EVIDENCE OF

the eight years when he resided in Wiirzburg, 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 shiae through all
time as a star of the first magnitude in the history
of medical science. In Wiirzburg, Yirchow 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 Wiirzburg,
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 Wiirzburg, 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

THE DOCTRINE OF DESCENT. 19

in the scientific treatment of disease, — all this was
either carried out or preconceived in "Wiirzburg ; and
even the celebrated " Cellular Pathology," a course of
lectures which he delivered during the first year and
a half after quitting Wiirzburg for Berlin, consists
only of the collected and matured fruits of which the
blossoms are due to Wiirzburg.

In the autumn of 1856 Virchow left Wurzburg 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 Yirchow 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
Wiirzburg with the scantiest means — a new proof of
the maxim enunciated by me, and hitherto never con-
futed, that " the scientific results of an institute are in
inverse proportion to its size." (See " The Aim and
Methods of Modern Evolution." ^)

Still more grave is the circumstance that, since
settling in Berlin, Virchow has more and more
exchanged his theoretical scientific activity for prac-

^ Jena, Zeitschriften fur Naturwisseuschaft, 1875. ^^ol. x. Supplement.

20 CERTAIN EVIDENCE OF

^ »

tical political life. It is well known how prominent
a part lie plays there in the Prussian Chamber of
Eepresentatives, how he raised himself to be the
leader of the party of progress, and, to give this politi-
cal position a broader basis, took part in the representa-
tion 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 Yirchow 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
difi&cult 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 Yirchow really believes that he
is doing a greater service to humanity by his practical

THE DOCTRINE OF DESCENT. 21

political life in Berlin than he formerly did by his
theoretical scientific work in Wiirzbnrg, 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 case.

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 pro-
gress of science — particularly when it advances so
rapidly and incessantly as is the case in our day. It
is therefore quite intelKgible that Yirchow 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 Yirchow of 1878
is hardly in a position to understand the youthful
Yirchow of 1848.

We have seen a similar mental change occur con-
temporaneously 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

22 CERTAIN EVIDENCE OF

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 Yon 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 Yon 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 Yon 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 Yon Baer gives us the ex-
planation of this striking contradiction. In 1834 he

THE DOCTRINE OF DESCENT. 23

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 Konigsberg 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 Yon Baer, as in Yirchow,
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 Yirchow's
case than in Yon Baer's, for this reason: morphological
knowledge was greatly lacking to Yirchow, while Yon
Baer possessed it in the highest degree. !N'ow mor-
phology 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 know-

24 CERTAIN EVIDENCE OF

ledge 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
Ouvier and splendidly developed by Johannes Miiller,
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 Linnaeus and Pallas, had
already been abundantly matured and utilised in many
ways for philosophic purposes by the synthetic prin-
ciples 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 (causae finales) ; they were
incapable of arriving at a true and clear perception of
effective mechanical causes (causce 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

THE DOCTRINE OF DESCENT. 25

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 endea-
voured 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 " (Grundziige der
vergleichenden Anatomic), by Carl Gegenbaur, 1870,
and the latest edition of his " Elements " (Grundrisses),
with the old text-books of that science.

26 CERTAIN EVIDENCE OF

Yircliow has no suspicion even of all these im-
measurable 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 .Miiller 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 Miiller'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 Yirchow in his
answer had really and thoroughly refuted this position,
instead of fighting with mere phrases and denuncia-
tions, this radical opposition would have been well
worthy of the fullest discussion. At the same time

THE DOCTRINE OF DESCENT. 27

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
faU 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. Yirchow 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, Yirchow 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 pene-
trated throughout by this principle of descent, that
every morphological inquiry which conscientiously
pursues a well-considered problem now assumes the

28 CERTAIN EVIDENCE, ETC.

doctrine of descent as granted and indisputable. Of
all this lie is ignorant, and so it is intelligible tbat lie
should continue to demand " certain proofs " of this
hypothesis, although those proofs have long since been
produced.

( 29 )

CHAPTEE III.

THE SKULL THEOEY AND THE APE THEORY.

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. Yirchow is, in fact, simply incom-
petent in the great question of evolution, as he is
deficient in the greater part of that knowledge — more
especially morphological knowledge — which is indis-
pensable to forming a judgment upon it. Hence on
the turning-point of the whole matter — viz., the pro-
blem 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
Eubus and Salix among the living plants of the present
period, and the Ammonites and Brachiopoda among

30 THE SKULL THEORY

extinct animals. Hence, too, Yirchow can have no
independent views as to the historical development of
the higher from the lower animals, because the abun-
dant living forms of the lower animals are almost
unknown to him, and because he has hardly any
conTjeption of the marvellous strides which hundreds of
industrious workers have made in this very depart-
ment within the last twenty years. But there can
be no doubt, indeed it is already universally acknow-
ledged, 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 " ^
I have conclusively proved that Monads must retain
their vast elementary importance whether the Bathy-
bius 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 understand-
ing the views of modern morphology.

"We must here examine more closely into this,

1 Vol. i. p. 293.

AND THE APE THEORY. 31

because it is precisely in tMs 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 descent.

The skull theory, as is well known, has for a long
time been a very favourite theme, not only with pro-
minent 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 impor-
tance; 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 correspon-
dence lies the only sound kernel of the sickly, over-
grown 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

32 THE SKULL THEORY

century, wlien 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 vertebrae.
This " vertebral theory " of the skull, which Yon
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

AND THE APE THEORY. 33

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 vertebrae 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
vertebrae, but that the separate bones of the skull are not
to be regarded as representing parts of such modified
vertebrae. The skull-bones of all recent vertebrate ani-
mals 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 vertebrae,
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 vertebrae, 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 Eays and

34 THE SKULL THEORY "

Sharks, are onthe whole the creatures which throw the
clearest light on the history of the lineage of the ver-
tebrata and on the organisation of our primeval fish-
natured ancestors. It is one of the particular merits
of Gegenbaur that he clearly and firmly estab-
lished the place in nature of the Selachians as the
common ancestors of all vertebrate animals from fish
up to man.

ISTone 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 Yertebrata." 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 explana-
tion of the most difficult morphological problems.
Gegenbaur might, therefore, with perfect right, enun-
ciate 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

AND THE APE THEORY. 35

transpired which contradicts that theory ; on the con-
trary, 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 Yirchow 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
Yirchow's latest contributions to the study of the
human skull, for any indication of his knowing or
appreciating Gegenbaur's investigations. On the con-
trary, 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 cranio-
logical science in the measuring of skulls, or cranio-
metry.

36 THE SKULL THEORY

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 — f.^., 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 mea-
suring 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 con-
tain 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

AND THE APE THEORY. 37

Selachians, would have yielded them more fruit and
have given them more light than long years of
describing and measuring human skulls, however
various.

Yirchow 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 compara-
tive 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

38 THE SKULL THEORY

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, understand-
ing 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, foi 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 Crea-
tion," 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

AND THE APE THEORY. 39

to man. In this, as in all researches into the deriva-
tion of our organism, we must distinguish between
the general theory of descent and the sjgedfic hypo-
thesis of descent. The general theory of descent
claims full and permanent value, because it is induc-
tively 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 trans-
mutation 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 investi-
gating the actual relations of cognate races of organic
forms more and more approximately.

Since the conception of the natural animal sys-
tem as a hypothetical genealogical tree, and the
4

40 THE SKULL THEORY

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 com-
pletest expression of the modern conception of struc-
tural affinity. If Yirchow 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 mor-
phology we have made by this phylogenetic work-
ing 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 ; Yirchow
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

AND THE APE THEORY, 41

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 ani-
mals from single-celled, of the Medusse 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 ISTature," 1863, so ad-
mirably 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 con-
tained 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

42 THE SKULL THEORY

character man differs less from tlie 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 systematisa-
tion, 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 Linnaeus, 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

AND THE APE THEORY. 43

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. ISTot one
opponent has suggested, or can suggest, any other
animal form that can serve as our nearest ancestor
than the ape. E'o 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 neces-
sity 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

44 THE SKULL THEORY

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
palseontology 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 ignor-
ance of this zoological question — in which I, as a
professional zoologist, must decisively declare his in-
competence. The reasons why such a solution of the
problem is not to be expected, the extraordinary im-
perfection of the palseontological record, the natural
impediments to the palseontological 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.

AND THE APE THEORY. 45

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 Yirchow was acquainted with
geology and palaeontology, and what a limited judgment
he can form of these historical causal relations.

( 46 )

CHAPTEK IV.

THE CELL-SOUL AND CELLULAE PSYCHOLOGY.

No attack in Yircliow's Munich address surprised me
so mucli, 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 funda-
mental views is here revealed, which stands in the
sharpest contrast to the mechanical monism formerly
upheld by the famous pathologist of Wurzburg.

In my Munich discourse (p. 1 2), I had alluded to
the "grand and fruitful application which Virchow
had made, in his system of ceUular pathology, of the
cell-theory to the general province of theoretic medi-
cine ;" and as a logical amplification of that idea, I
asserted emphatically that we must ascribe an inde-
pendent soul-life to every individual organic cell.
" This conception is validly proved by the study of
infusoria, amoebae, and other one-celled organisms ; for,
in these individual, isolated, living cells we find the
same manifestations of soul-life — feelings, and ideas

THE CELL-SOUL. 47

(mental images), will and motion, as is in the higher
animals compounded of many cells " (p. 13). Yirchow
now rises np 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 pro-
cesses 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 state-
ments in Virchow's paper, I involuntarily asked my-
self, " Can this be the same Virchow from whom,
twenty-five years ago, I learnt in Wurzburg that the
soul-functions of man and animals depend on me-

48 THE CELL-SOUL

clianical processes in the soul-organs ; that tliese 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 Yirchow's complete change in all fundamental
scientific principles. For the ceUular 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 renuncia-
tion of the latter or an untenable and inconsequent
position. To explain this astonishing meta-psychosis,
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. Ac-

AND CELLULAR PSYCHOLOGY. 49

cording to the monistic (or realistic) soul-hypothesis,
the " soul " is nothing more than the sum or aggre-
gate 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, Con-
sciousness, Intellect, and Eeason. 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; there-
fore 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 mechanistia If psychical mechanics — psycho-
physics — 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 conscious-
ness) to a mathematical " soul-formula."

According to the opposite, or dualistic (or spiritu-
alistic) soul-hypothesis, the soul is, on the contrary, a

so THE CELL-SOUL

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 imponder-
able " 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

AND CELLULAR PSYCHOLOGY. 51

the conservation of force, lias, 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 Wiirzburg with
those of the older and mystical Yirchow 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 Yirchow, 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 interpreta-
tion of nature," and that " without it no natural science
can exist." On this point Yirchow says well in his
discourse on " Ejtforts at Unity in Scientific Medicine,"

52 THE CELL-SOUL

1 849 : — " Life is only a peculiar sort of raechanics,
thougii it is indeed the" most complex form of me-
chanics ; 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 Yirchow'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 con-
science 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

AND CELLULAR PSYCHOLOGY. 53

prejudices of tlie dualistic doctrine, and for my con-
version to the monistic, as to Eudolf Virchow ; for it
was his superior guidance which most firmly con-
vinced me, and many others, of the exclusive import-
ance 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 pheno-
mena 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 1 849,
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 consequences ! "

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

54 THE CELL-SOUL

utterances in Virchow's Municli address of 1877, we
perceive that he could not give the lie more fiercely
to his former fundamental opinions than he has there
done. E'ot quite twenty years have passed by, and
yet, in the course of that time, in Yirchow'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 dif-
ferent 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 Yirchow'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 remark-
able 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 Yirchow's earlier me-

AND CELLULAR PSYCHOLOGY. 55

chanistic 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 window."

Almost more remarkable is Yirchow'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 Vh^chow 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 Yirchow 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 charac-
teristic 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-ceUs, and so forth, are derived, are

S6 THE CELL-SOUL

originally tlie 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 histo-
logical 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 evo-
lution 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 obser-
vation so undoubtedly in the commonest forms of in-
fusorial animals — 'for instance the Ciliata, that one of
their most persevering observers, Ehrenberg, asserted
undeviatingly to the day of his death that all Infusoria

AND CELLULAR PSYCHOLOGY. $7

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, Zeitschrif-
ten, 1873, vol. vii. p. 5 1 6). And just as we must attri-
bute 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 proto-

58 THE CELL-SOUL

plasm, everywhere exhibits the same psychic proper-
ties 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 inde-
pendence, 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 Sipho-
nophora, as I have briefly shown in my article on
" The Cell-soul and Soul-cells " (Deutsche Eundschau,
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 indivi-
dual persons of which this stock (or Cormus) is com-
posed 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

AND CELLULAR PSYCHOLOGY. 59

foundation of empirical psychology," I believed I was
drawing an inference quite to Yirchow'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 Yirchow had long since become unfaithful to
his most important biological principles, and had de-
serted 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, Medusae, 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 ceU theory as
"mere trifling with words."

N"ext 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

6o THE CELL-SOUL, ETC.

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 de-
veloped simultaneously with its material substratum,
, and. subsequently, after birth, it appears in full activity.
According to Yirchow'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.

( 6i )

CHAPTEE V.

THE GENETIC AND DOGMATIC METHODS OF TEACHING.

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
prop*ositions, 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,

62 THE GENETIC AND

Yirchow'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 sub-
jective, 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"

Earely indeed has such a treasonable attempt on
liberty of doctrine been made by a prominent repre-
sentative 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 convic-
tions with as much right as he had to construct them
from inquiry into objective facts. And where, gene-
rally speaking, is the limit to be found between objec-

• DOGMATIC METHODS OF TEACHING. 63

tive 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 depart-
ments 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 con-
trary, all human knowledge as such is subjective. An
objective science which consists merely of facts with-
out 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 — know-
ledge 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
5

64 THE GENETIC AND

first principles of matliematics migM 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 mathe-
maticians, 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 ? Un-
doubtedly 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 ?

DOGMATIC METHODS OF TEACHING. 65

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 ]ess than
proved. Or optics ? Optics certainly appertain to
the most important and completest branch of physics,
and yet the nndiilatory theory of light, which we
accept now as the indispensable basis of optics, rests
on an unproved hypothesis, on the subjective assump-
tion 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 Yirchow's view, Newton on the contrary
transgressed greatly by teaching this erroneous hypo-
thesis ; for even in " exact " physics none but " inde-
pendent and certain facts " are to be taught and

66 THE GENETIC AND

established by " experiment as the highest means of
proof." Physics as a whole, as resting on mere un-
proved 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 posi-
tively 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. ISTo 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,

DOGMATIC METHODS OF TEACHING, 67

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 experi-
ment, " 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 investic^ation but not of teachinoj.

Having thus convinced ourselves that chemistry as
well as physics, those " exact sciences," those " mechani-
cal " 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 prin-
ciples 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 conxposition, the origin and development of our
globe. According to Virchow this too must be limited
to the description of ascertained facts, such as the struc-
ture of mountain masses, the character of the fossils

68 THE GENETIC AND

they contain, tlie 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 begin-
ning to end on unproved hypotheses. For even to the
present day the Plutonic and J^ep tunic theories are
disputing the field, and to this day we know not as to
many of the most important rocks, whether they ori-
ginated 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, mys-
terious "Lusus naturse," 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 semiaalis), and so
forth.

But I am wrong ! for with regard to petrifactions,
Yirchow is in the highest degree speculative, and
accepts without any hesitation the rash hypothesis
that fossils are actually the remains of extinct or-

DOGMATIC METHODS OF TEACHING, 69

ganisms, althougli no " certain proof " whatever can
be offered in its favour, and altliough 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 subjec-
tive 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 palseontolo-
gical 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 palaeontologists, 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 mam-

10 THE GENETIC AND

mals. 'But this is a quite inadmissible hypothesis
devoid of any " certain proof ! " Where, then, are the
other bones ? Let ns see them ! till then we decline
to believe in them. Accordino^ to Yirchow, we onerht
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 scepti-
cism, 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 uuiversally-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 lack-
ing in that comprehensive knowledge of comparative
morphology which is indispensable to it; nay, com-
parative 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

DOGMATIC METHODS OF TEACHING. 71

speculative levity with which even the sceptic Yirchow
in the " Primeval History of Man " and " Fossil Anthro-
pology," 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 hypo-
theses have blossomed- out so freely as in anthropology
and ethnology, so-called. All the phylogenetic hypo-
theses which I myself have put forward in my " Evolu-
tion of Man " as to the animal ancestry of man, Or in
my " I^atural 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
Yirchow rejects in a lump, are, critically considered as
hypotheses, far better grounded in facts, far better
supported by facts, than the majority of those innumer-
able airy and fanciful hypotheses with which, for the
last twelve years, the " Archiv fiir Anthropologic " and
" Zeitschrift fiir Ethnologic," edited by Yirchow and
Bastian, have filled their columns. This last perio-
dical 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.

72 THE GENETIC AND

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 vari-
ous and contradictory hypotheses which have been put
forward as to the antiquity and first appearance of the
human species ; and Yirchow 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

DOGMATIC METHODS OF TEACHING. 73

actual experiment " as the highest means of proof,"
which gives evidence for these " certain facts " ? The
whole discussion in general about pre-historic man,
which Yirchow 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 Yirchow, 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

74 THE GENETIC AND

explanatory hypotheses raise those dead masses of facts
to the place of true and livmg 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 physio-
logy depends, and by applying which Yirchow 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 doc-
trine 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 con-
cej)tion 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 dis-
cerned 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,

DOGMATIC METHODS OF TEACHING. 75

and what consequences mnst be inferred from the cell-
theory, and attempts have not been wanting to upset
it altogether and to treat it as worthless. The anato-
mist Henle, of Gottingen, 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 con-
trary, is the only genuine article. jN'ot long since a
bulky volume in quarto appeared, by one Herr ISTathu-
sius-Konigsborn, 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. Yirchow formerly was one of the vic-
torious opponents of the Gottingen 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 coinplete change
Yirchow has undergone in his most important principles,
and what an utter metapsychosis in this special pro-

76 THE GENETIC AND

vince, than his famous axiom, uttered in 1855 —
" Omnis cellula e cellula." That is unquestionably
the boldest generalisation to which the youthful, inde-
pendent Yirchow ever attained, and one on which he
justly prided himself not a little. He himself re-
peatedly 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-nu-
cleated cytods, as in the Gregarinae, Myxomycetee and
others. N'ay 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 Yirchow, 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 experi-
ments seemed to point to the hypothesis of free cell-
formation. That guiding axiom, which so powerfully
furthered the cell -theory, Yirchow, from his present
standpoint, must wholly condemn as a crime against

DOGMATIC METHODS OF TEACHING. 77

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 know-
ledge and to form it into a living science. These new
theories and the hypotheses on which they were
founded, Yirchow 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 insufi&ciently 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 patho-
logical phenomena in the simplest manner, and yet
it was afterwards proved to be false. In spite of

78 THE GENETIC AND

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 investi-
gations. 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 teach-
ing." That Yirchow, in his course of instruction,
every day belied this, his present view of teaching,
that he every hour taught his disciples some un-
proved 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 pre-
cisely 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 pro-
pounded to us his personal hypothesis for the eluci-
dation 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

DOGMATIC METHODS OF TEACHING, 79

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 strug-
gling mind anything better, or more conducive to cul-
ture, 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 en-
deavours 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 self-evident.

8o THE GENETIC AND

Finally, there remains nothing but theology. Theo-
logy 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, incre-
dible as it sounds, Yirchow, the sceptical, opponent of
dogma, the leader of the fight for "liberty of science,"
Yirchow 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 general."

The shouts of triumph of the whole clerical press
over Yirchow's Munich address is thus rendered per-
fectly 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 Yirchow, the
" notorious materialist," the " advanced radical," the
" great supporter of the atheism of science," is so sud-
denly 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

DOGMATIC METHODS OF TEACHING. 8l

" Hosanna in the highest ! " Only one thing is to be
regretted, that Yirchow has not more clearly defined
which of the many different church-religions is the
only true one, and which of the innumerable and con-
tradictory 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 Eeformed or the
Lutheran confession, whether the Anglican or the
Presbyterian dogma, whether the Eoman 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 opinion.

At any rate, the " instruction of the future, accord-
ing to Yirchow," will be greatly simplified if he will do
this. Por 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

82 THE GENETIC AND

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. Yirchow,
" 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 sup-
planted 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 instruc-
tion 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 con-
trary, 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 Yirchow's dis-
course. Thus at the beginning of his address he
glorifies Lorenz Oken and deeply laments "that he,
that highly-valued and honoured master, that ornament

DOGMATIC METHODS OF TEACHING. 83

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 sacriJSced 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
Eudolf Virchow at this day is most violently striving ?
Did not Oken himself proceed farther in the construc-
tion 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 philo-
sophy ? And this makes the irony seem all the greater
with which Virchow at the beginning of his address

84 THE GENETIC AND

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 teach-
ing, 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-waist-
coat 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,. ^nd anthro-
pology— 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

DOGMATIC METHODS OF TEACHING. 85

any closer discussion of tliis 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.

Eor 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 astonish-
ing 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 instruc-
tion ? 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 im-
portant advance which has been made in our views
during the present century should be left to the dis-
cretion 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 ? "

86 THE GENETIC AND

I must here be permitted to take Yirchow exactly
at his word. I endorse alrdost all that he has said in
these and the following sentences. ■ The only difference
in our views is this, that Yirchow regards the theory
of descent as an unproved and unproveable hypothesis;
I, on the contrary, as a fully established and indispen-
sable theory. How then will it be if the teachers of
whom Yirchow 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 Yirchow 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 com-
pletely penetrated by the doctrine of descent, phylo-
genetic 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 work-
ing zoologists, are convinced by inductive methods of
the truth of the doctrine of descent." And Yirchow
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

DOGMATIC METHODS OF TEACHING. 87

of teaching as it is of inquiry, for the two are intrinsi-
cally and inseparably connected. And so it is not in
vain that it is written in section i 5 2 of the German
Code, and in section 20 of the Prussian Charter,
" Science and her teaching shall be free ! "

( 88 )

CHAPTEE VI

THE DOCTRINE OF DESCENT AND SOCIAL DEMOCRACY.

Every great and comprelieiisive theory which affects
the foundations of human science, and which, conse-
quently, 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

THE DOCTRINE OF DESCENT, ETC. 89

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 compre-
hensive 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 prin-
ciples of the development-theory of the day, and there-
fore is incompetent to judge it. Moreover, Yirchow, 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 Yirchow de-
nounces 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

90 THE DOCTRINE OF DESCENT

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
" Yaterland," 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 tliink
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 im-
practicable." And he proceeds to add, " And why has
not Yirchow 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

AND SOCIAL DEMOCRACY. 91

Virchow brings again&t tlie doctrine of evolution, lie
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 in-
equality 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

92 THE DOCTRINE OF DESCENT

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 ex-
tremely 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 ex-
travagant 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 — Darwin-
ism, 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 demo-
cratic, and least of all socialist. The theory of selec-
tion teaches that in human life, as in animal and plant

AND SOCIAL DEMOCRACY, 93

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 posi-
tion 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, there-

94 THE DOCTRINE OF DESCENT

fore, Darwinism, logically carried out, has, according to
Vircliow, " 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 social-
ism of the day can find any encouragement in these
efforts, and how the horrors of the Paris Commune
can he 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 un-
qualified 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 train-
ing 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 Yu'chow, I lack alike the gift and the training for

AND SOCIAL DEMOCRACY. 95

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 acti-
vity 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 them-
selves 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 ?

96 THE DOCTRINE OF DESCENT

ISTotMng, 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 doc-
trines, 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 doc-
trine 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 doctrfties and for the extirpation of heretics of

AND SOCIAL DEMOCRACY. 97

other creeds, aril that the Jews have been guilty of
towards the heathen, the Eoman 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 hetero-
dox Christians ! think only of the Inquisition in the
Middle Ages, of the inconceivable and inhuman bar-
barities committed by the " most Christian kings " of
Spain, by their worthy colleagues in Prankfort, 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 Eoman Popes is

98 THE DOCTRINE OF DESCENT, ETC.

the best answer to this question. And just as* these
"Vicars of God on earth" did, so did their subordi-
nates 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 con-
trast 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 civilisa-
tion 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.

( 99 )

CHAPTEE VII.

IGNOEABIMUS ET RESTKINGAMUR.

The dangerous attempt which Yirchow 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. Un-
doubtedly the famous " Ignorabimus-speech " of Du
Bois-Eeymond, 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 Vir-
chow's " Eestringamur speech " of 1877, at the fiftieth
meeting of the same society, forms the second part.

That brilHant and powerful essay by Du Bois-Eey-
mond " 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

loo IGNORABIMUS ET RESTRINGAMUR.

overlooked in admiration of the brilliant accessories of
the essay. Indeed this frequently happens with Du
Bois-Eeymond'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 funda-
mental 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 2 2 and 2 3 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-Eeymond 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 conscious-
ness. ISTow, first of all, as has already been said in

IGNORABIMUS ET RESTRINGAMUR. loi

the preface to the "Evohition of Man," we must
raise a decided protest against the air of infalli-
bility with which Du Bois-Eeymond 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 ])old 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 pro-
blem 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 Zoo-
logique" 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

I02 IGNORABIMUS ET RESTRINGAMUR.

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-Eeymond fixes for human knowledge, in my
opinion they are undoubtedly identical. The pro-
blem 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-Eeymond
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 con-
ditions, 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, " Ignorabimus."

The light way in which Du Bois-Eeymond here

IGNORABIMUS ET RESTRINGAMUR. 103

passes over the most important part of Ms subject is
truly surprising; as if it were ultimately indifferent
whether we have before us one single insoluble funda-
mental 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-Eeymond 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 him-
self; 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 difi&cult 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

I04 IGNORABIMUS ET RESTRINGAMUR.

whicli at first are troublesome and have to be learnt
with consciousness and reflection — as for instance
walking, swimming, singing, and so fortb-^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 con-
sideration of the soul-life of animals, that their con-
sciousness is slowly, gradually, and serially developed,
and that a long unbroken series of steps leads from
unconscious to conscious existence. From these com-
parative and genetic experiences we may draw the
conclusion that consciousness, like sensation ' and voli-
tion, 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 con-
sciousness, as well as the soul in general, as a neces-
sary function of certain cells.

How little Du Bois-Eeymond is acquainted with the
facts of comparative and genetic psychology, nothing

IGNORABIMUS ET RESTRINGAMUR. 105

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." Beg-
ging your pardon ! Every naturalist who is familiar
with the comparative morphology and physiology of
the lower animals will here put in a decided contradic-
tion, 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 fur-
nished 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-func-
tions. 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

io6 IGNORABIMUS ET RESTRINGAMUR.

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 sensi-
tive 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 ani-
mals; 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 proto-
plasm is the same in the vegetable-cell of the Mimosa
as in the animal- cell of the Hydra. How far Du Bois-
Eeymond is from discerning this, and how deeply he

IGNORABIMUS ET RES TRING AMUR. 107

is still entangled in nenro-psy ecological 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 natura-
list 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 gan-
glionic centres co-extensive with the psychic capacity
of such a Soul " (!)

In other respects we will not deny that Du Bois-
Eeymond stands far nearer to our recent evolution-
theory than Yirchow; nay, that from year to year
he has always pronounced more and more emphati-
cally in favour of the theory of descent as the one
possible explanation of morphological phenomena;
indeed, Du Bois-Eeymond 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 Qgg 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 bear-
ing the title " Darwin versus Galiani " (1876), that Du

io8 IGNORABIMUS ET RESTRINGAMUR.

Bois-Eeymond is still far from -understanding the full
significance of transmutation as affording a mecha-
nical 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 theo-
retical section-tables of the strata of the earth's crust
are to geology.

If Du Bois-Eeymond 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

IGNORABIMUS ET RESTRINGAMUR. 109

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 his-
tory 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-Eeymond's — [the idea which had
already been anticipated by Leibnitz, that the " innate
ideas," — intuitions a 'priori — have originated by trans-
mission from primordial experience, i.e., empirical, db
posteriori convictions], was distinctly enunciated by me
long before Du Bois-Eeymond (as he omits to mention),
in I Z66, 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-Eeymond had prac-
tically 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 pon-
derous " Tgnorabimus."

,-The question has been repeatedly asked why two
such prominent Berlin biologists as Yirchow and Du

no IGNORABIMUS ET RESTRINGAMUR.

Bois-Eeymond availed themselves of the particularly
solemn occasions of the fiftieth anniversary and of the
fiftieth meeting of the German naturalists and physi-
cians to lay lance in rest against the progress and free-
dom 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, in-
deed, in much greater measure than Du Bois-Eeymond
— appears to justify this inquiry. I believe I can con-
tribute 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 — offi-
cials 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-Eeymond alike, lies in their unacquaint-
ance 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

IGNORABIMUS ET RESTRINGAMUR. in

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 ex-
planation 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-Eeymond, 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 tfiat there are few univer-
sities where the study of morphology is so behindhand
as at the University of BerKn. Fully twenty years
have now elapsed since the great Johannes Miiller
died, the last naturalist who could command all the
departments of biology. The three great provinces of
science which had been reunited into a triime king-
dom under his powerful sceptre, were then divided
among three professors' chairs : Du Bois - Eeymond
took that of physiology, Yirchow, theoretical pathology
(pathological anatomy and physiology), and the third,
and most important chair, that of morphology (human

and comparative anatomy, including the history of
7

112 IGNORABIMUS ET RESTRINGAMUR.

evolution) fell to Boguslaus Eeichert. This choice
was, as is now universally admitted, an incomprehen-
sible 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 Eeichert they selected an elderly school
anatomist cramped hy 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
t)f Berlin during these two decades (for instance, the
recent confused work by Tritsch on the brain of
fishes) with the rich mine of invaluable work produced
during the preceding twenty years by Johannes Miiller
and his crowd of disciples.

But, as if this were not enough, Eeichert took
advantage of his influential position to hinder as far
as possible all scientific study of morphology. For

IGNORABIMUS E f RESTRINGAMUR. 1 1 3

example, he, with the co-operation of his colleagues,
carried through that pretended " reform " of medical
examination which puts the so-called Tentamen pliy-
sicum in the place of the philosophicum ; philosophy
was entirely eKminated. 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 pre-
vious 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 laiow-
ledge. 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. N'ow 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

114 IGNORABIMUS ET RESTRINGAMUR.

understanding of organic life can never be obtained
without due relative study of both. The masterly
and incomparable teaching of Johannes Miiller 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
Eeichert and his colleagues, is as far behind that of
Miiller's day, twenty or thirty years ago, in all general
comprehension of the typical organism, as it is in
advance of it in specialist acquirements.

In medical, as in all other scientific learning, the
highest aim does not consist in seeking to accumu-
late 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 lias practically

IGNORABIMUS ET RESTRINGAMUR. 115

digested a considerable number of the most important
facts, and has critically co-ordinated them to a harmo-
nious whole. It is precisely under this aspect that
transmutation is of such inestimable value to mor-
phology; it enables us to rise from the bare empirical
knowledge of numberless isolated facts to a philoso-
phical 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. ISTay, Adolf
Bastian, the most zealous of all the Berlin opponents
of our doctrines, has insisted on these facts with pecu-
liar satisfaction. Of all the conspicuous naturalists of
Berlin only one accepted the doctrine of transmutation
from the beginning with sincere warmth and full convic-
tion, being, indeed, persuaded of its truth even before
Darwin himself. This was the gifted botanist Alex-
ander Braun, who is lately dead — a morphologist who
was equally distinguished by the extent of his com-
prehensive knowledge of details, as by his philosophical

ii6 IGNORABIMUS ET RESTRINGAMUR,

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 ex-
ample 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 natur-
alists 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. Yirchow'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 pertina-
cious 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.

IGNORABIMUS ET RESTRINGAMUR. 117

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 Genera-
tiones," 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 pre-con-
ceived 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-3I-)

But it would appear that it is the fate of that most

1 1 8 IGNORABIMUS ET RESTRINGAMUR,

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 18 12, Lamarck's theory of descent,
founded in 1809, had to wait fully fifty years before
Darwin, in 1859, showed it to be the greatest acquisi-
tion of modern science ; and during that period, in
spite of all the progress made in empirical science,
how persistently this most comprehensive of all bio-
logical theories was combated. We need only re-
collect how, in 1830, the celebrated George Cuvier
silenced its most eloquent supporter, Geoffrey 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 Geof-
frey had already grasped truths of the highest signifi-
cance, whUe 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

IGNORABIMUS ET RESTRINGAMUR. 119

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 ini-
mical 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 (parti-
cularly the Liberal "ISTational-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 pre-
served 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,

I20 IGNORABIMUS ET RESTRINGAMUR,

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 desir-
able 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 intel-
lectual 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-Eeymond raises

IGNORABIMUS ET RESTRINGAMUR. 121

the cry of " Ignorabimus," and Eudolf Vircliow his
still more audacious one of " Eestringamnr," as the
watchwords of science, then, from Jena, let the
shout be raised and echoed from a hundred other
universities — "Impavidi progrediamur ! "

lUTr?J^-Jf2.3^ (3',/3,^:

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book of this series, he will spend only $12.40.

NOW EEADT:

I.— LIGHT.

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

By ALFMED M. MATEM and CHAELES BABNAED.

II.— SOUND:

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

By ALFEED MAE8HALL MAYER,
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 Mem-
ber of the New York Ophthalmological Society.

In Active Peepaeation:

III. Vision and the Nature of Light.
rv. Electricity and Magnetism.
V. Heat.
YI. Mechanics.
VII. Chemistry.

Vm. The Art of experimer ting with Cheap and Simple In-
struments.

D. APPLE TON <& CO., Publishers, 549 & 551 Broadway, New York.

TEE EXPERIMENTAL SCIEJ^CE SERIES.

LIGHT:

A Series of Simple, Entertaining, and Inexpensive Experijnents in the
Phenomena of Light, for the Use of Students of Every Age.

BY ALFRED M. MAYER and CHARLES BARNARD.

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

"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 Remew .

"This work describes, in simple language, a number of experiments illus-
trating.the principal properties of light, by means of a beam of sunlight admitted
into a dark room, and various contrivances. The experiments are highly in-
genious, 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 experi-
menting.' " — 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 experi-
ments 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 chil^
dren 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 TorJc 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 TorTc Scientific American.

"The experiments are for the most part new, and have the merit of com-
bining 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."— -dmeyjco^i Journal of Science and Arts.

D. APPLETON & CO., 549 & 551 Broadway, New York.

THE EXFEBIMEKTAL SCIEJfCE SERIES.

SOUND:

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

By ALFRED MARSHALL MAYER,

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 satis-
factory manual for those who have no time for perusing a larger work. It con-
tains 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 Review.

" It would really be difficult to exaggerate the merit, in the sense of consum-
mate 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 iu 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."— JSostow Courier.

D. APPLETON & CO., 549 & 551 Broadway, New York.

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,

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The Culture demanded by Modern Life.

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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 Edwakd L. Youmans,
M. D. 1 vol., 12mo. Cloth, |2.00.

The Popular Science Monthly.

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

Containing instructive and interesting articles and abstracts of articles,
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Accounts of important scientific discoveries ;

The application of science to the practical arts ;

The latest views put forth concerning natural phenomena, by savants
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The volumes begin May and November of each year. Subscriptions
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D. APPLET ON & CO., Publishers, 549 & 551 Broadway, New York.

A New and Valuable Work for the Practical Mechanic and Engineer.

CICLOPMATFrnfEDHCHAinCS.

A DICTIONARY OP

MECHANICAL ENGINEERING AND THE MECHANICAL ARTS.

HiliUSTEATED BY 5,000 ENGRAVINGS.

Edited, by PARK BENJAMIN, Ph. D.

CONTKIBUTORa.

T. A. EDISON, Ph. D.
RICHAiiD H. BULL, C. E.
SAMUEL WEBBER, C. E.
Prof. DE VOLSON WOOD.
CHARLES E. EMERY, C.E.
JOSHUA ROSE, M. E.
PIERRE DE P. RICKETTS, Ph. D.
Hon. ORESTES CLEVELAND.
W. T. J. KRAJEWSKI, C. E.
S. W. GREEN, Esq.
JOHN BIRKINBINE, C. E.
HENRY L. BKEVOORT, C. E.
Lieut. A. A. BOYD, U. S. N.

ABRAM L. HOLLEY, C. E.
COLEMAN SELLERS, M. E.
Prof. C. W. McCORD.
IRVING M. SCOTT, Esq.

F. A. McDowell, c. e.

H. A. MOTT. Jr., Ph. D.
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GEORGE H. BENJAMIN, M.D.
THERON SKELL, C. E.
WILLIAM KENT, C. E.
W. E. KELLY, Esq.
F. T. THURSTON, C. E.
JOHN HOLLINGSWORTH, EsQ.

Appletons' CyCLOPiEDiA OF Applied Mechanics of ISYQ is a new work,
and 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 Inter-
national 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 me-
chanical 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 Farts, 50 cents each.
Subscriptions received only for the entire work of Twenty-four Parts.

D. APPLETON & CO., Publishers, 549 So 551 Broadwat, New York.

17867(

i

Date Due

DeC-3'5'i

m>.

JUN 22

JUN 29

OCT

4m

1997

b 7

BOSTON COLLEGE

3 9031 01652361 5

1

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