AT THE UNIVERSITY
It was botany itself that thwarted all these designs. The examination
had passed off happily. Rooms were taken at Jena, at the Easter of 1852,
for the advanced study under Schleiden. Then the indefatigable collector
had an adventure on a cold March day. He spent hours in the wet meadows
by the river Saale, searching for a rare plant, the squill (_Scilla
bifolia_). He met with the fate of the angler in the story, who fell
into the water in his haste to secure his big pike. He landed the fish,
but not himself. The plant was found, but Haeckel’s zeal was punished
with a severe rheumatism. He had to go home to his parents at Berlin to
be tended. At Berlin he begins his studies, and the event to some extent
decides his career. It would now be many years before he would see Jena
again; and through his efforts it would become one of the leading
schools, not of botany, but of zoology—a school of _philosophical_
zoology, however, in the sense of Schleiden.
Berlin had secured a botanist of the first rank a year before, Alexander
Braun. He, too, was a thoughtful botanist, who would in his way agree
very well with Schleiden. He was convinced that botany did not wholly
consist in the determination of new plant forms and the almost fruitless
effort to set up a system on which all particular diagnoses would be
rigidly played as on a piano. He believed that there must be a more
profound conception of it, which would take “form,” as such, as one of
its problems, and would aim, not at the formation of as large a
collection as possible, but at the construction of a science for which
Goethe had long ago found a name—morphology, or the science of forms. It
happened that Braun was a friendly visitor at the house of Haeckel’s
parents at Berlin. The now convalescent freshman became devoted to him,
body and soul; they became close friends, not merely master and pupil.
Berlin at that time afforded many an opportunity for practical
botanising. Rare marsh-plants then flourished in the bed of the Spree,
which has since been cleared. The Botanical Garden was full of good
things. Haeckel used to tell with pride, long afterwards, with what
readiness he flung himself into the work, practical as well as
theoretical, on these excursions with Professor Braun. “On one of our
botanical expeditions we wanted to get a floating chara from a pond.
Braun took off his boots in his usual way in order to wade to the spot.
But I was before him. I quickly undressed, forgot my naughty rheumatism,
and swam to the spot, to bring him a quantity of the plant he wanted.
That was my first piece of heroism, perhaps my greatest.”
But in all this pleasant botanising there was no serious outlook on his
future profession. Haeckel’s father, with his official way of looking at
things, could not reconcile himself to scientific research as an
avocation. It is an old belief that the way to all preoccupation with
the science of living things lies through medicine. One may question
that to-day. It was the rock on which Darwin nearly came to grief. A man
may be a very gifted botanist, yet be quite unfitted for the medical
profession. One must have a real vocation to become a physician, more
than for any other calling, or else it is a hopeless blunder. The
talents are divided in much the same way as between the historian and
the soldier. It is true that the two may be united, but it is equally
true that very good historians have made very poor soldiers. What the
medical man learns in his studies is, of course, always valuable. But it
offers no test of personal talent for scientific research, nor should it
be supposed that a capacity of this kind would be able, by mere formal
study, to acquire the true qualities of a physician. We must learn to
appreciate the physician’s calling too much ever to look on it as an
incidental occupation. It always reminds me of the amiable notion of the
Philistine, that a man with a turn for poetry must first take up some
solid profession, and then, once he is “in the saddle,” pour out verses
in his leisure hours. Poetry can never be a mistress: it demands
marriage or nothing. Otherwise—well, we have instances enough.
Haeckel himself afterwards said that he only acceded to his father’s
wish, that he should study medicine, with a botanical mental
reservation. He thought of going through the discipline conscientiously
until he became a physician, and then secure a place as ship’s doctor,
and travel over the world and see the tropics. Things turned out very
differently. He never became a medical man such as his father had
wished, but he passed over the profession into zoology. Botany remained
the lost and never-forgotten love of his youth. When we look back on his
whole career we can see that he was, on the whole, fortunate. Zoology
afforded a richer, more abundant, and more varied material at that time.
It proved to be more “philosophical.” He went after his father’s asses
and found a kingdom. But to him personally it seemed to be an
unmistakable renunciation—the first in an active career that was to see
many resignations.
* * * * *
“He goes farthest who does not know where he is going.”
Haeckel once applied this motto to himself and his star, in a humorous
after-dinner speech. With this kind of safe predestination he reached
Würtzburg in the autumn of 1852 as a medical student. Medicine had in
those days received an entirely new theoretical basis from Würtzburg—a
basis that was calculated to attract a young inquirer, who brought much
more of the general Faust-spirit to his work than aspiration to the
profession and the doctor’s cap, or the practical side.
Let us recall for a moment how medicine had gradually reached the
position of an independent science. Medicine was the outcome of a remote
mythical epoch. It was content with the effect of certain venerable
traditional medicaments on the living body, but knew little or nothing
of the inner structure of the body on which it tried its drugs. The
dissection and examination of even a corpse was regarded as a deadly
sin, and was visited with secular punishment. Scientific medicine did
not exist until this prohibition was removed; its first and most
necessary foundation was anatomy, the science of the bodily structure
and its organs. The art of “cutting up” bodies had seemed too revolting.
Moreover, no sooner had the science of anatomy been founded than the
range of the human eye itself was considerably enlarged. The microscope
was invented. A new world came to light in the dissection of the body.
Beyond their external appearance it revealed the internal composition of
the various organs. The eye sees a shred of skin, a piece of intestine,
or a section of the liver. The microscope fastens on a tiny particle of
this portion of the body, and reveals in it a deeper layer of
unsuspected structures. It is well known in the history of microscopic
discovery that the more powerful lenses and the improved methods of
research were only gradually introduced, and enabled students to found a
new and much profounder anatomy. As soon as this science appeared it was
given the special name of “histology,” or the science of the tissues
(_hista_). Its particular achievement is the discovery that in man, the
animal, and the plant, all the parts of the body prove, when
sufficiently magnified, to be composed of small living elements, which
are known as cells. The discovery of the cell was made in the latter
part of the third decade of the nineteenth century. These cells join
together in homogeneous groups in order to accomplish one or other
function in the body, and thus form its “tissues.” Their intricate
structure is unravelled by the histologist, microscope in hand. It is
evident that in this way a new basis was provided for anatomy, and
therefore also for medicine. In the fifties Würtzburg was the leading
school of histology, or the science of these tissues composed of cells.
Albert Kölliker, professor of anatomy there since 1847, published his
splendid _Manual of Histology_ at the very time when Haeckel was
studying under him. Franz Leydig, a tutor there since 1849, was working
in the same direction. The third member of the group, made professor in
1849, was Rudolf Virchow, a young teacher then in his best years. It was
Virchow who did most to bring practical medicine into line with
histology. As the vital processes in the human body seemed to him, with
his strict histological outlook, to be traced back always to the
tissue-building cells, he concluded that disease also, or the
pathological condition of the body, and therefore the proper field of
the medical man, was a process in these cells. Man seemed to him to be a
“cell-state”: the tissues were the various active social strata in this
state: and disease was, in its ultimate source, a conflict in the state
between the citizens, the tissue-forming cells, that normally divide the
work amongst them for the common good. Pathology must be cellular
pathology. The science was already being taught by Virchow at Würtzburg,
and the dry bones of it were covered with flesh for his hearers. But his
ideas were not published until a few years afterwards (1858).
In the first three terms Haeckel studied chiefly under Kölliker and
Leydig. They taught him animal and human embryology, as it was then
conceived. Embryology was the science of the development of the
individual animal or man, the description of the series of changes that
the chick passes through in the egg or the human embryo in the womb.
This science, also, had been profoundly affected by the invention of the
microscope. Firstly, the spermatozoa, the active, microscopically small
particles in the animal and human sperm, had been discovered. Then, in
the twenties, Karl Ernst von Baer had discovered the human ovum. The
relation of these things to the cell-theory was clear. It was
indubitable that each of these male spermatozoa and each female ovum was
a cell. They melted together and were blended into a new cell in the act
of procreation, and from this, by a process of repeated cleavage of
cells, the new individual was developed with all his millions of cells
and all the elaborate tissues that these cells united to form. A whole
world of marvellous features came to light, but the key to the
unriddling of them was still wanting.
However, the Würtzburg school was at least agreed as to _method_, which
was the main thing; its leaders were determined to press on to the
solution of these problems on purely scientific lines. Everything was to
be brought into a logical relation of cause and effect, and there was to
be no intrusion of the supernatural, no mysticism. Natural laws must be
traced in the life of the cells and in the history of the ovum and the
embryo. The cells were to be regarded in the same way as the astronomer
regards his myriads of glittering bodies. In this way the science of
histology had been founded, and embryology had assumed a scientific
character in the hands of Von Baer. The microscope kept the attention of
students to facts, and did not suffer them to lose themselves in the
clouds. Thus a foundation-stone was laid in Haeckel’s thoughts which he
would never discard.
In the later years of the Darwinian controversy he was destined to come
into sharp conflict with both Virchow and Kölliker. Each of them came to
look on him as the sober hen does on the naughty chick it has brought
into the world, that madly tries to swim on the treacherous waters of
Darwinism. But forty years afterwards—after many a knife-edged word had
been thrown in the struggle—the aged Kölliker was one of those who
entered their names in the list of men of science who erected a bust in
the Zoological Institute at Jena in honour of Haeckel’s sixtieth
birthday.
However, it was a different, an apparently trivial, yet, as it turned
out, most momentous interest that quickened him during these University
years.
The impulse to microscopic research, that had led to the foundation of
histology and embryology, had brought about a third great advance
which had an important bearing on zoology. When we stroll along the
beautiful shore of the Mediterranean at Naples to-day, with eyes bent
on the blue surface from which Capri rises like a siren, and on the
cloud-capped Vesuvius with its violet streaks of lava cutting across
the green country, we notice in the foreground of the picture a stout
building, with very large windows, planted with the boldness of a
_parvenu_ amongst the foliage. It is the “Zoological Station,” built
by Dohrn, a German zoologist, at the beginning of the seventies. Anton
Dohrn was one of Haeckel’s first pupils, and was personally initiated
by him into the study of marine life, at Heligoland in 1865.
Zoologists who work in the station to-day find it very comfortable.
Little steamers with dipping apparatus bring the inhabitants of the
bay to them. There is a large aquarium at hand. You sit down to your
microscope, and work. The material is “fresh to hand” every day. There
are now many of these stations at well-exposed spots on the coast in
various countries—sea-observatories, as it were, in which the student
examines his marine objects much as the astronomer observes his
planets and comets and double stars at night. To-day, when a young man
is taking up zoology, and he is asked what university he is going to,
he may say that he is going down to the coast, to Naples, to do
practical work. When the long vacation comes, swarms of professors go
from the inland towns to one or other seaside place, as far as the
purse will take them. All this is a new thing under the sun. The
zoologist of the olden days sat in his study at home. He caught and
studied whatever was found in his own district. The rest came by
post—skins, skeletons, amphibians and fishes in spirit, dried insects,
hard shells of crustacea, mussels and snails of all sorts; but only
the shells always, the hard, dry parts of star-fishes, sea-urchins,
corals, &c. Animals of the rarest character were thrown away because
they could not very well be preserved in spirit and sent from the
North Sea or the Mediterranean to Professor Dry-as-dust. In this state
of things the advance in microscopic work brought no advantage. But at
last it dawned on students that the sea is the cradle of the animal
world. Whole stems of animals flourished there, and there only. Every
wave was full of innumerable microscopic creatures, of the most
instructive forms. Amongst them were found the young embryonic forms
of familiar animals. At last the cry, “To the sea,” was raised. The
older professor of zoology had suffered from a kind of hydrophobia. It
was not possible to teach very much at Berlin about the anatomy,
histology, and embryology of the sea-urchin from a few dried flinty
shells. At Würtzburg, animals were subtly discussed by men who had
never made a journey to see them, while they were trampled under foot
every day by the visitors bathing in Heligoland. They must move. It
was not necessary to go round the world: a holiday journey to the
North Sea or the Mediterranean would suffice. Every cultured man had
always considered that he must make at least one pilgrimage to classic
lands before his education was complete. It was only a question of
changing material. They were not to confine themselves to examining
ruined temples and aqueducts, but to take their microscopes down to
the coast, draw a bucketful of sea-water, and examine its living
contents—the living medusa and sea-urchin, and the living world of the
swarming infusoria. But it was like the rending of the great curtain
of the temple. Zoology seemed to expand ten-fold, a hundred-fold, in a
moment. A room in an obscure inn by the sea, a microscope, and a
couple of glasses of salt-water with sediment every morning—and the
finest studies at Paris and London were as ploughed land, without a
single blade, in face of this revelation. It was a Noah’s ark in the
space of a pinch of snuff.
One day the young medical student heard, in the middle of his histology
and zoology, that Kölliker had come back from Messina. He had been
studying lower marine life there. In 1853, two young men were together
in the Gutenberg forest near Würtzburg. One of them, Karl Gegenbaur, had
been abroad with Kölliker. With his impressions still fresh, he tells
Haeckel about his zoological adventures in the land of the Cyclops.
Gegenbaur, eight years older than Haeckel, was by birth and education a
typical Würtzburger. He, too, had studied medicine, and had practised at
the hospital. But he had already advanced beyond that. His stay at
Messina had been devoted entirely to zoological purposes. A year later
he would be teaching anatomy at Würtzburg, and a year later still he
would be called to Jena. From that time he began to be known as a master
of comparative anatomy—especially after 1859, when his _Elements_ of the
science was published, a classic in its way that still exercises some
influence.
There is nothing romantic in his career, nor could we seek any element
of the kind in a man of Gegenbaur’s character. But his young and
undecided companion seemed to catch sight of a new ideal as he spoke. He
would complete his medical studies, and then shake himself free of
surgery and hospital. He would take his microscope down South, where the
snowy summit of Etna towered above the orange-trees, and study the
beautiful marine animals by the azure sea and the white houses, in the
orange-laden air, and drink in ideas at the magic fount of these
wonderful animal forms, and live out the lusty, golden years of youth on
the finest coast in Europe. From that moment Haeckel felt a restless
inspiration. He had no idea what it was that he was going to investigate
at Messina; and he certainly did not know when and how he was to get
there. But he continued his medical studies with a vague hope that it
was only preliminary work; that some day he would do what his friend
Gegenbaur had done.
They were very good friends, these two. They were drawn together by the
strong magnetism of two true natures that understood each other to the
golden core, though in other respects they were as different as
possible. Gegenbaur was no enthusiast. His ideal was “to keep cool to
the very heart.” But he was at one with Haeckel in a feeling for a broad
outlook in scientific research. He never shrank from large connections
or vast deductions, as long as they were led up to by a sober and
patient logic. This logical character he afterwards recognised in
Darwin’s idea of evolution, and so the friends once more found
themselves in agreement, and for a long time they were a pair of real
Darwinian Dioscuri. This feeling for moderation and at the same time for
far-reaching logic was combined in Gegenbaur with a certain steady and
unerring independence of character. He made little noise, but he never
swerved from his aim. What he accomplished with all these qualities, in
many other provinces besides Darwinism, cannot be told here. It may be
read in the history of zoology. He had, as far as such a thing was
possible, a restful influence of the most useful character on Haeckel.
If we imagine what Darwinism would have become in the nineteenth century
in the hands of such men as Gegenbaur, without Haeckel, we can
appreciate the difference in temperament between the two men. With
Gegenbaur evolution was always a splendid new technical instrument that
no layman must touch for fear of spoiling it. With Haeckel it became a
devouring wave, that will one day, perhaps, give its name to the
century. In other natures these differences might have led to open
conflict. But Haeckel and Gegenbaur show us that, like so many of our
supposed “differences,” they can at least live together in perfect
accord in the freshest years of life, each bearing fruit in its kind.
* * * * *
When we find Haeckel intimate in this way with Gegenbaur, his senior by
eight years, we realise how close he was at that time to the whole of
the Würtzburg circle. The two generations were not yet sharply divided,
as they subsequently were. Most of them fought either with or against
him at a later date, but they belonged, at all events, to the same
stratum. But the split between the two generations was felt when one
pronounced the name of Johannes Müller, of Berlin—the physiologist (not
the historian).
All who then taught histology, embryology, comparative anatomy, or
cellular pathology at Würtzburg had sat at his feet, either spiritually
or in person. Johannes Müller, born at the beginning of the century, was
appointed Professor of Anatomy and Physiology at Berlin the year before
Haeckel was born. That indicates the distance between them. It was in
Müller’s incredibly primitive laboratory that, as Haeckel tells, the
theory of the animal-cell was established by his assistant, Theodor
Schwann, after Schleiden had proved the vegetal cell. Müller himself had
founded histology in his own way. He was the real parent of the idea
that the zoologist ought to go and work by the sea. We have a model of
this kind of work and at the same time a superb work for embryological
matters in Müller’s epoch-making _Studies of the Larvæ and Metamorphoses
of the Echinoderms_. He had brought comparative anatomy beyond the stage
of Cuvier, to a point where Gegenbaur could begin. From his school came
Rudolf Virchow, who applied the cell-theory to medicine, and Emil du
Bois-Reymond, who opened out a new path in physiology by his studies of
animal electricity. Müller had done pioneer work with remarkable vigour
in all the various branches of research, diverging afterwards to an
enormous extent, that pursue these methods. The many-headed (young and
half-young) generation, in which Haeckel was growing, saw the whole
previous generation embodied in the single name of Müller. He seemed to
be a kind of scientific Winkelried, except that the fifty spears he bore
on his breast were so many lines of progress emanating from him alone.
Johannes Müller had the great and splendid gift of never lying on the
shoulders of his pupils with an Alpine weight of authority. It was a
secret of his personality that we admire but can hardly express in words
to-day. Everybody learned from him what a great individuality is. He
exerted a kind of moral suggestion in teaching men to be free, great,
enlightened, and true. His pupils have worked at the development of his
ideas with absolute freedom. No part of them was to be regarded as
sacred, and, as a matter of fact, in the chief questions no part has
remained.
One approaches the inner life of a man like Müller with a certain
timidity, and asks how he became what he was. There can be no question
that the fundamental trait of his character was a peculiarly deep
religious feeling. At heart he was a mystic. The whole magic of his
personal influence sprang from these depths. By profession he was a
physiologist, an exact scientist. Never did he swerve a hair’s breadth
from the iron laws of research. But beneath it all was a suppressed glow
of fervour. Every one who understood him, every one who was a true pupil
of his, learned it by a kind of hypnotism. Externally he was all for
laborious investigation, whether in dissecting a star-fish for you or
classifying fishes—though he would have a full sense of your ardent
longing for an inner trust in life and a philosophy of life. Both
elements might change considerably in the pupil: the method of
investigation without—the ideal of the comprehensive vision within. But
what never left any man who had followed Müller was the warning cry that
these things, within and without, should go together; that, in the
larger sense, it is not possible to count the joints in the stalk of an
encrinite without feeling a thrill in the deepest depth of the mind and
the heart.
It is so common a spectacle in history for disciples to condemn their
masters with cold smiles that we forget how pitiful it is. No pupil of
Johannes Müller has ever felt that he had done with him, and might quit
him with ingratitude. He had pupils, it is true, who did not lack belief
in themselves, and who became famous enough to give them a sense of
power; men who have eventually come to conclusions diametrically opposed
to those that Müller had taught them. Yet they respect him. Living
witnesses still tell of the glance that bored into you, and could not be
evaded. But there must have been a greater power in the man than this
piercing glance. It was a glance that survived the grave, and laid on
one a duty; a glance that shot up in the darkness of memory if the duty
was not fulfilled—the duty of going to the foundation of things. Whether
you are examining the larva of an echinoderm or the light of a distant
star, God is there. Whether you explain your echinoderm-larva in this
way or that; whether you believe your star to be a sun or a burnt-out
cinder; whether you conceive God in this way or another—you shall feel
that the bridge is there in absolutely everything. Every glance into the
microscope is a service of God. It was Goethe’s deepest sun that threw a
great, radiant spark out of this curious, dark, angular, unintelligible
jewel.
Such a man was bound to be more than Kölliker, Virchow, and Gegenbaur to
Haeckel. Müller was still teaching at Berlin, and Haeckel’s best star
brought him to sit in reality at the feet of the great teacher, who
could so well speak soul to soul to him.
At the Easter of 1854 Haeckel returned from Würtzburg to Berlin. He was
now twenty years old, and it was at this juncture that, to use his own
phrase, the vast impression of Müller fell on him. A portrait of Müller
still hangs over the desk in his study in the Zoological Institute at
Jena. “If I ever become tired at my work,” he says, “I have only to look
at it to get new strength.” The influence of the much older man, who,
however, died at a far earlier age than Haeckel will do, only lasted for
a short time. But Haeckel has preserved a memory of him that is only
eclipsed by the memory of one other man—Darwin. Müller did not live to
read Darwin’s decisive work, so that these two great ideals of Haeckel’s
never crossed each other, either for good or evil. He himself felt that
there was a pure evolution from one to the other in his mind.
In the summer of 1854 he studied comparative anatomy under Müller, for
which Kölliker had sufficiently prepared him. He has recorded his first
impressions. “I soon got to know him personally, but I had so great a
respect for him that I did not venture to approach him more closely. He
gave me permission to work in the museum. I shall never forget the hours
I spent there, drawing skulls, while he walked up and down, especially
on Sunday afternoons. Often when he went past me I wanted to ask him
something. I went up the step with beating heart and took hold of the
bell, but returned without venturing to say anything.” Müller took some
notice of the zealous young student. When the long vacation came round
in August, and the master, following the new custom, packed up his
bundle in order to spend two months on practical work by the sea, he
allowed Haeckel to go with him. Müller’s son and the later Professor La
Valette joined the party. They went to Heligoland. Müller taught his
pupils his simple method of studying the living subject. There was no
witchcraft in it, but it had had to be invented by some one. They put
out to sea in a small boat. A little net of linen or fine gauze, with a
wide opening and short body, was fastened on a pole. The mouth of the
net was thrust directly under the surface or a little deeper, vertically
to the surface, and the boat was slowly rowed forward. The contents of
the filtered sea-water remained in the meshes of the net, and were from
time to time emptied into a glass containing sea-water. “I shall never,”
says Haeckel, “forget the astonishment with which I gazed for the first
time on the swarm of transparent marine animals that Müller emptied out
of his fine net into the glass vessel; the beautiful medley of graceful
medusæ and iridescent ctenophores, arrow-like sagittæ and serpent-shaped
tomopteris, the masses of copepods and schizopods, and the marine larvæ
of worms and echinoderms.” Müller called these very fine and generally
transparent creatures, of whose existence no one hitherto had had any
idea, “pelagic sweepings” (from _pelagos_, the sea). More recently the
word “plancton” (swimming matter) has been substituted for his phrase.
As we now send whole expeditions over the seas to study “plancton,” the
word has found its way into ordinary literature. The regular anglers who
were then in Heligoland must have looked on this subtle work with a
butterfly net as a sort of pleasant joke born from the professional
brain. The young student must have made an impression on them with his
vigour, though he had not yet turned himself into a marine mammal,
living half in the water for days together. They called him a
“sea-devil.” What pleased the master most in him was the talent he
already showed of quickly sketching the tiny, perishable creature from
the surface of the sea while it was fresh. Haeckel had been passionately
fond of drawing from his early years. Now the old bent agreed with the
new zeal for zoology. “You will be able to do a great deal,” Müller said
to him. “And when once you are fairly interested in this fairy-land of
the sea, you will find it difficult to get away from it.” The dream of
Messina, that Gegenbaur had conjured up, seemed to draw nearer.
[Illustration:
FISHING IN HELIGOLAND IN 1865.
Anton Dohrn (Naples). Richard Greeff (Marburg). Ernst Haeckel (Jena).
Max Salverda (Utrecht). Pietro Marchi (Florence).
]
These lively days at Heligoland provided Haeckel with the material for
his first little zoological essay. It dealt with the development of the
ova of certain fishes (_On the Ova of the Scomberesoces_, published in
Müller’s _Archiv_ for 1855). Müller lent him ova from the Berlin
collection to complete his study. It is the same volume of the _Archiv_
in which, in Reichert’s introduction, the great controversy breaks out
over Virchow’s pregnant assertion that each human being is a state
composed of millions of individual cells.
Haeckel remained with Müller at Berlin for the whole winter, and was
drawn more and more into the province of comparative anatomy, or, to
speak more correctly, zoology. The official Professor of Zoology at
Berlin at the time was really the aged Lichtenstein, who had occupied
the chair since 1811. Haeckel has humorously described himself in later
years as self-taught in his own subject, saying that he had attended
many most excellent colleges, but never visited an official school of
zoology. The only opportunity to do so at the time was under
Lichtenstein, but that professor bored him so much that he could not
attend his lectures. Lichtenstein was a venerable representative of the
old type of zoologist; his ideal was to give a careful external
description of the species on the strength of specimens chosen from a
well-stocked museum. A whole world lay between these surviving followers
of Linné and the splendid school of Johannes Müller.
However that may be, the fact was that under these alluring attractions
Haeckel’s studies were drifting from the medical profession to an
“impecunious art.” But as medical work had been chosen, if only as a
temporary occupation, Haeckel had to tear himself away from the great
magnet, at the Easter of 1855, by removing to a different place. He
chose, as the least intolerable compromise, to return to Würtzburg. At
all events we find him spending three terms there. I have already said
that Rudolf Virchow was one of the distinguished Würtzburgers at the
time who sought most keenly the solution of the new problems of biology
on the medical side. Hence Virchow had to help him to find the bridge
between the work he really loved and the work he was obliged to do. As a
fact, Virchow directed the whole of his studies on this side in the
three terms.
Virchow was not so fascinating as Johannes Müller, even in his best
years. But it was something to be initiated into medical science by such
a man. A later generation has, unfortunately, grown accustomed to see
mental antipodes in Virchow and Haeckel. In 1877 they had a controversy
with regard to the freedom of science that echoed through the whole
world of thought. Yet seventeen years afterwards Haeckel himself (who
was first attacked by Virchow), looking back on the days he spent at
Würtzburg, had nothing but grateful recognition to say of Virchow. “I
learned,” he says in 1894, “in the three terms I spent under Virchow the
art of the finest analytic observation and the most rigorous control of
what I observed. I was his assistant for some time, and my notes were
especially praised by him. But what I chiefly admired in him at
Würtzburg was his wide outlook, the breadth and philosophic character of
his scientific ideas.”
The theory that Virchow put before his pupils was pure Monism, or a
unified conception of the world without any distinction of physical and
metaphysical. Life was defined, not as a mystic eccentricity in an
orderly nature, but plainly as a higher form of the great cosmic
mechanism. Man, the object of medical science, was said to be merely a
higher vertebrate, subject to the same laws as the rest.
We can see very well that this was quite natural. If there was any man
likely to put forward such views it was Virchow. He had passed through
Müller’s school, but was now one of the younger group who, even during
Müller’s life, were gradually adopting certain very profound views on
life and man, without any particular resistance on the master’s part.
The chief characteristic of nearly the whole of this group was the lack
of the volcanic stratum below of deep and personal religious feeling; in
Müller this had been throughout life an enchained Titan among the rocks
of his logical sense of realities, yet it had given a gentle glow and
movement to the floor of his mind. Rudolf Virchow was the coolest,
boldest, and clearest-minded of the group. He went to the opposite
extreme. If Müller was standing on a volcano, which he only repressed by
the giant force of his will—a nature that was above all master of
itself—Virchow, on the contrary, was standing on a glacier, and he had
never taken the trouble to conceal it. I should not venture to count him
amongst the instinctively Monistic minds, in the sense of Goethe, to
whom the unity of God and nature, the inorganic and the organic, the
animal and the man, comes as an ardent and irresistible feeling. But it
would have been strange if, in those years and in the middle of the
whole scientific current of his time, his own organ, his icy logic, had
not led him to the same conclusion; that it is a simpler method of
research to believe in natural law alone, to regard the living merely as
a complex play of the same forces that we have in physics and chemistry,
and to consider man, with the bodily frame of an ape-like mammal, to be
really such an animal. I believe, indeed, that Virchow never abandoned
this simple solution in his own mind at any part of his career. The
controversy he afterwards engaged in ran on different lines. It seems to
me that at an early stage of his development he became convinced that
there must be limits to scientific inquiry, not on logical, but on
diplomatic grounds; because it is not an absolute agency, but only a
relatively small force amongst many more powerful institutions, the
Church, the State, and so on. Hence it would have to respect limitations
that were not drawn from its own nature; in given cases it would have to
keep silent in order not to jeopardise its existence as a whole. It is
my firm belief that this diplomatic attitude as such would lead to the
destruction of all pursuit of the truth. It carefully excludes the
possibility of any further martyrdoms, but at the cost of science’s own
power to illumine the world. In my opinion the free investigation of the
truth is an _absolute_ right. Churches, States, social orders, moral
precepts, and all that is connected with them, have to adjust themselves
to this investigation, and not the reverse.
However, the point is that under Virchow—more particularly under
Virchow, in fact—Haeckel would be educated into the general attitude
with regard to God, nature, life, and man, to which he has since devoted
his whole energy. In spite of Goethe—and who would be likely to take
Goethe as his guide in his twenty-first year?—the ardent young student
was as yet by no means firmly seated in the saddle. He grubbed, and
sought, and rejected. In his _Riddle of the Universe_ he tells us that
he “defended the Christian belief in his twenty-first year in lively
discussions” with his free-thinking comrades, ... “although the study of
human anatomy and physiology, and the comparison of man’s frame with
that of the other animals, had already greatly enfeebled my faith. I did
not entirely abandon it, after bitter struggles, until my medical
studies were completed, and I began to practise. I then came to
understand Faust’s saying, ‘The whole sorrow of humanity oppresses me.’
I found no more of the infinite benevolence of a loving father in the
hard school of life than I could see of ‘wise providence’ in the
struggle for existence.”
When the three terms of medical training were over, he received another
impulse to his own particular interest in science. Kölliker invited him
in August, 1856, to spend the two months’ holiday with him on the
Riviera. It was the first Mediterranean school of zoology, though as yet
only a kind of “payment on account.” On the journey he made the
acquaintance of the zoological museum at Turin and its well-travelled
director, Filippo de Filippi, and he saw the grandeur of the Maritime
Alps on the Col di Tenda. The master, Kölliker, Heinrich Müller, Karl
Kupffer (afterwards professor at Munich), and he established themselves
at Nice, and fished for all sorts of creatures with the Müller-net at
Villefranche. Fortunately, Müller himself happened to be visiting the
Riviera at the same time, and they received a direct stimulus from him.
The first result of this journey in the summer and autumn was that
Haeckel secured his degree with a zoological-anatomical work, instead of
with a strictly medical treatise. As he had done from Heligoland two
years before, he now brought home from the Mediterranean the material
for a short technical theme. He again spent the winter at Berlin to put
it together. It was an histological study of the tissues of crabs, and
therefore lay in the province of the articulates, an animal group, it is
curious to note, which he has not entered into more fully in the course
of his long and varied work as special investigator. At Nice he made a
thorough study of the nerve-tubes of the spiny lobster and other
available marine crustacea, and discovered several remarkable new
structural features in them. At Berlin he entered upon a minute
microscopic study of the common craw-fish. His dissertation for the
doctorate embodied the main results of his research. It was entitled _De
telis quibusdam Astaci fluviatilis_, and was printed in March, 1857. It
appeared the same year in an enlarged form in Müller’s _Archiv_, with
the title _The Tissues of the Craw-fish_. On March 7th he received his
medical degree, Ehrenberg, the great authority on the infusoria,
presiding. In the customary way the young doctor had to announce and
defend several theses. One of them is rather amusing in view of later
events.
He most vigorously contested the possibility of “spontaneous
generation.” The meaning of the phrase is that somewhere or at some time
a living thing, animal or plant, has arisen, not in the form of a seed
or germ or sprout from a parent living thing, but as a direct
development out of dead, inorganic matter. Haeckel had not made a
personal study of the subject. What he said in his thesis was merely a
faithful repetition of Müller’s opinion. At that time it was believed
that science had empirically disproved spontaneous generation. An old
popular belief held that fleas and lice were born every day from
non-living dirt and dust, but that had been refuted long before. No egg,
no animal: every living thing develops from an egg. This had been laid
down as a fixed rule. When the microscope revealed an endless number of
tiny creatures in every drop of stagnant water, in the air and the dust
and the soil, it was a question whether the rule was not wrong. Surely
these simplest of all living things, apparently, were born by
spontaneous generation? However, the question was believed to have been
settled in two ways. Schwann, the co-discoverer of the cell-theory, had
made certain experiments which seem to prove directly that even these
tiny beings, the infusoria and bacteria, were never formed in a vessel
containing water and dead matter, if it had been carefully assured
beforehand that the minute living germs of these animals that floated in
the air could not penetrate into the vessel. At the same time Ehrenberg
and others stoutly denied that the infusoria were the “simplest”
organisms, or that they could conceivably be born in that way. They
declared that the infusoria were “perfect organisms” in spite of their
smallness. The belief that these tiny creatures consisted of “one cell,”
and so formed, as it were, the ultimate elements of the plant and animal
worlds on the lines of the cell-theory, was seriously menaced, and
apparently on the way to be destroyed. Finally, the tapeworm and similar
parasites had been declared to evolve by a kind of spontaneous
generation from the contents of the intestines. But this also was proved
to be untrue. Thus there was ample material for a solid dogma: there was
no such thing as spontaneous generation. The dogma, moreover, harmonised
with the prevailing belief in a special vital force and a radical
distinction between the living and the dead, which was still shared in a
subtle form by even a man like Müller. The dogma was formulated.
Spontaneous generation was struck out of the scientific vocabulary as
unscientific and a popular superstition. The young doctor, duly
initiated into these ideas of the time, could not resist the temptation
to give his own kick to the fallen theory. Yet how strangely things have
changed since then! Two years afterwards Haeckel ceased to believe in a
special vital force; he was now absolutely convinced that there were
unicellular beings; his whole theory of life seemed to demand
spontaneous generation as a postulate, and he even doubted the force of
the experiments of Schwann and others. Haeckel himself became the
keenest apostle of the theory of spontaneous generation. Whenever it is
mentioned to-day, we think of the weight of his name which he has cast
in the scale in its favour. So the leaves change even in the forest of
science: yesterday green, to-day red and falling, to-morrow green once
more. On the same branch as the dogmas we find the correctives growing,
that will at length split them open and cast them as empty husks to the
ground.
The history of Haeckel’s medical doctorate can be written in a few plain
and touching lines. After receiving his degree he was sent by his
prudent father, to keep him away from crabs and other monsters of the
deep, to Vienna for a term, to do hospital work under Oppolzer, Skoda,
Hebra, and Siegmund. All that we find recorded of this term is that his
old love of botany revived in earnest. Immense quantities of dwarf
Alpine plants were collected. When the traveller passed by the spot
twenty-four years afterwards on a quiet autumn Sunday, on his way to
take ship at Trieste for the tropical forests and giant trees of Ceylon,
the memory of Schneeberg and the Rose-Alp came upon him like a dream.
However, the hospital work, together with a short span of cramming in
the winter at Berlin, must have had some effect, as he passed the
State-examination in medicine. In March, 1858, he was a “practising
physician.” He had in his hand the crown of prudent ambition—and he felt
like a poor captive. There was one source of consolation—Johannes
Müller. While one was near him there was a possibility of more real
work. He discussed with him the plan of the study of the development of
the gregarinæ (parasitic protozoa), which he wanted to conduct in
Müller’s laboratory in the summer of 1858. Then he was stricken, like so
many others, with the thunderbolt of the news of Müller’s sudden death,
on April 28th of the same year. What must he do now? He began to
practise. It is said on his own authority that he fixed the hours of
consultation from five to six in the morning! The result was that during
a whole year of this philanthropic occupation he had only three
patients, not one of whom died under his earnest attention.
“This success was enough for my dear father,” says Haeckel. We can well
believe it.
The kindly old man consented to one more year of quite extravagant
study, in which all was to come right. It was to be a year of travel, in
Italy. He was to devote himself to the study of marine animals, not
merely for pleasure, but earnestly enough for him to find a basis for
his life in the result. This he succeeded in doing. Like the children of
fortune, who at the very moment when they cannot see a step before them
make a move that the Philistine regards as the safest and last refuge,
Haeckel becomes engaged that very year to his cousin, Anna Sethe. After
that, in January, 1859, he goes down to the coast. He makes for the blue
Mediterranean, which he already knows will prove anything but an
“unprofitable sea” for him. He will conjure up treasures of science from
its crystal depths with his Müller-net; then on to fortune, position,
marriage, and the future. The fates have added a world-wide repute, if
they have denied many a comfort.
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