Heligoland--Giessen Congress--Leuckart--Visit to Leo Metchnikoff
at Geneva--Socialist gatherings--Metchnikoff's discovery
appropriated by Leuckart--Naples--Kovalevsky--Comparative
embryology--Embryonic layers--Bakounine and Setchénoff--
Cholera at Naples--Göttingen--Anatomical studies--Munich;
von Siebold--Music--Return to Naples--Intracellular digestion.
Elie still had his Licentiate thesis to prepare. In order to do so, he
decided to spend two months in the island of Heligoland, of which the
flora and fauna were very attractive to naturalists. In spite of his
previous failure, his parents made no objection to his departure; they
gave him the little money they could spare and Elie started, in 1864.
As soon as he arrived in Heligoland he became absorbed in his work.
He proceeded with his idea of bringing light upon the genealogy
of organisms through the study of isolated forms outside definite
groups.[7]
[7] He made researches on a very singular annulate worm, the
_Fabricia_.
His ardour in his work attracted the attention of several German
scientists, one of whom introduced him to the celebrated botanist
Cohn, who soon became interested in him. During the walks which they
took together, they held scientific conversations full of interest for
the youth. Cohn advised him to work under the celebrated zoologist
Leuckart. Elie received this counsel with enthusiasm, but there was
a great difficulty, which was the lack of money to prolong his stay
abroad. He did not wish to ask for more from his parents and decided on
the following plan, which he expounded in the following letter to his
mother, the constant confidante of all his aspirations:
HELIGOLAND, _Aug. 12, 1864_.
DEAR MAMMA, ... I am thinking of staying here another month, after
which I shall go (at least that is my desire) for ten days to
Giessen, where there will be a General Congress of naturalists and
physicians from the whole of Europe. This Congress tempts me so much
that I want to do my utmost to attend it.
Besides all the scientific benefit that I shall reap from
conversations with scientists, I can also study Professor Leuckart's
rich collections. This would complete the studies which I am
successfully pursuing at the seaside.
In order to realise my ardent wish to profit by such treasures, I
must remain three weeks longer at Heligoland, travel to Giessen and
live there for ten days; all that out of the money which was to keep
me here until the 26 Aug. only.... Therefore, instead of living in
the hotel, I have taken a room at a fisherman's, for half the price;
instead of a dinner and coffee I eat what I can get and I only spend
90 centimes a day for my food. (Food is dear, as all the provisions
come from Hamburg and from England.) Instead of changing my linen two
or three times a week, I only do so once or twice, which allows me to
spend less on laundry.
The money thus economised, together with the sum which I had put
aside for my first installation at Petersburg, constitutes a
sufficient capital to provide the following joys and advantages: 1°,
I shall stay three weeks longer at the seaside, which will allow me
to get on with my researches and to increase my collections; 2°, I
shall attend the Congress; 3°, I shall be able to study Leuckart's
collections and take advantage of his books and counsel.
I beseech you not to look upon this description of my present life as
a complaint or a murmur; on the contrary I am delighted to procure
so many advantages at so small a cost; I am happy, too, to be able
to assure you in all conscience that I am not wasting the money that
you have found for me with so much care and affection. I only wish I
could find myself oftener in the same conditions.
Please also believe that my health is in no way suffering from my
work. I give you my word that until now I have not had a single
headache.
Moreover, I do not think work is at all detrimental to health; I see
here several German scientists who could fell an ox with their fist!
Altogether I beseech you not to be anxious on my account; you have
quite enough painful preoccupations without that, and I am in such
excellent circumstances that there really is nothing to worry about.
I kiss your hands many times.
Yours affectionately,
ELIE METCHNIKOFF.
_P.S._--Write to me oftener. Every word from you is so precious to me!
He did not tell his mother that he never had enough to eat. Neither did
he wish Cohn and his other acquaintances at Heligoland to notice it,
and he carefully concealed his style of living.
He went to Giessen for the opening of the Naturalists' Congress and
read with success two papers dealing with his researches at Heligoland.
Engelmann (who was to become well known as a physiologist) and he
were the youngest members of the Congress, and their extreme youth
attracted general attention. Elie at last made Leuckart's acquaintance;
he was charmed by him and definitely decided to begin at once to work
under his direction, and, as his stay abroad had thus to be prolonged,
he asked and obtained a _bursa_ from the Russian Ministry of Public
Education.
The results of his researches at Heligoland had led him to suppose
that the Nematodes (of the worm type) formed an independent group; he
now proposed to settle that question. Leuckart allowed him to work in
his laboratory during his absence for the holidays; Elie immediately
set to work and discovered a very curious and quite novel case of
alternation of generations; hermaphrodite and parasitic Nematodes
giving birth to a free bisexual generation.
Delighted with his discovery, he hastened to communicate it to
Leuckart, who was incredulous at first but had to give way to evidence
when Elie showed him all the intermediary stages. Still the German
scientist was obviously annoyed that this discovery should have been
made in his absence and independently from him. He proposed to the
young man that they should continue researches in collaboration and
publish a joint memoir. Elie accepted joyfully. In his ardour he worked
too much, and fatigued his eyesight so that he was forced to limit his
microscopical researches to a few hours a day, and Leuckart advised him
to take a rest.
It happened that Elie's brother Leo had just settled in Geneva and
invited him to stay with him; Elie started to join him. The brothers
had not met for a long time. Leo had been travelling and had resided
in many different places. He was an extraordinarily gifted man,
impulsive, brilliant, and artistic, but restless and incapable of
adhering to a steady course of action; he scattered his activities and
did not therefore produce all that his rich nature was capable of.
He had a remarkable gift for languages; he knew not only a number of
European languages but also several Oriental languages, having been
in the East, where he had occupied a post of agent in navigation and
commerce. He afterwards lived in Italy, took an active part in the
Garibaldi movement and was wounded. A clever painter, he also had real
literary talent; handsome, witty, agreeable, he was a most attractive
personality. Elie had great affection for him.
He found him surrounded with young men and studying a map. They were
discussing the acquisition of a piece of ground in Italy in order to
found a socialistic community, and Leo, who knew the country, was
to choose the locality. Elie was at once made acquainted with the
political questions of the day; the young scientist was unfavourably
impressed, for the whole reduced itself to party questions and dogmatic
discussions founded on hollow grounds. Accustomed as he already was to
positive scientific methods, vague and arbitrary theories could not
satisfy him.
On the other hand, he was deeply impressed by the personality of the
celebrated socialistic Russian writer, Herzen, who resided in Geneva at
that time. The young revolutionaries considered him as too literary and
too much of a theoretician; they themselves yearned for a direct-action
policy. Leo Metchnikoff, however, admired him fervently. Meetings
often took place in Herzen's rooms; he used to read to his guests with
wonderful effect his yet unpublished manuscript _Passé et pensées_.
A great and powerful figure, the superiority of his intelligence was
almost crushing, while his sparkling wit and the nobility of his whole
being endowed him with an incomparable and irresistible personal charm.
Metchnikoff often said that no man had left a deeper impression on his
life. As a politician, however, he had not the same prestige in his
sight.
This sojourn in a revolutionary centre interested him much, but had
the result of confirming his conviction that science was immeasurably
superior to politics, and he congratulated himself on the path he
had chosen. After he had rested, he started to return to Giessen and
stopped at Heidelberg, a centre for Russian students who gathered
around Helmholtz, Virchow, and Bunsen. He hurried to the library
in order to see scientific periodicals; one of the first that came
under his eyes was a number of the _Göttingen News_, containing a
memoir by Leuckart on the Nematodes which they had studied together;
Leuckart described, in his own name, their common researches and also
those personal to the young man, whom he only mentioned incidentally.
Elie was shocked and indignant. On his return to Giessen he tried to
obtain an explanation from Leuckart but in vain; the latter eluded his
questions and gave him no answer.[8]
[8] All this episode was described by Metchnikoff in 1866 in
a separate publication with great restraint and in a very
moderate tone.
In his despair, the youth confided in Claus, a professor of zoology
whose acquaintance he had made at the Congress, who told him that
Leuckart was in the habit of such dealings, and urged Elie, as an
independent stranger, to reveal the fact. He pressed this with so much
insistence that Elie ended in following his advice; he sent an article
stating the case to Dubois-Reymond's journal. He then departed from
Giessen without taking leave of Leuckart.
Having had a _bursa_ of 1600 roubles a year granted him for two years
by the Russian Ministry of Public Instruction, he was able to undertake
a journey to the shores of the Mediterranean in order to pursue his
researches.
He had heard of a very talented young zoologist, Alexander Kovalevsky,
who also knew him by hearsay and had written him a letter full of
enthusiasm concerning the rich Mediterranean fauna and the facilities
for work in Italy. He therefore went to Naples on leaving Giessen.
Though the journey in itself had but a secondary attraction for him, he
had expected to receive a strong impression; but his imagination had
painted such grandiose pictures of the country that he had to cross,
that the reality disappointed him, and Italy, like Switzerland on a
former occasion, fell very far short of his expectations. He stopped
at Florence, which made but a poor impression on him. Museums fatigued
him, for he saw a great deal too many works of art all at once without
any previous preparation. Architecture and the plastic arts in general
did not take any hold of him. During his rapid journey he only saw the
country quite superficially and had no time to become impregnated with
its beauty. He therefore hastened towards Naples, where his work and
Kovalevsky attracted him far more.
He found in Kovalevsky a young man with shy but cordial manners and
the clear sweet eyes of a pure child, obviously an idealist. He had
for science an absolute cult, the sacred fire of the worshipper; no
sacrifice was too great, no difficulty too repellent for his ardour.
On a closer acquaintance, the small, timid young man proved to be a
hard fighter where science was concerned. The two young men formed
an excellent impression of each other, and a friendship was started
between them which was to last a lifetime. Though very different
from each other, they met on common ground, a passion for science.
They worked with the greatest energy, going together on zoological
excursions, exchanging their ideas, discussing their aspirations; a
similarity of tastes lent great attraction to their friendship.
At Giessen, Elie had read Fritz Müller's _For Darwin_, a book which
had a decisive influence on the future direction of his researches.
Fritz Müller, in his embryological works on certain crustaceans, had
been the first to confirm in a concrete manner Darwin's evolutionist
theories; he had thus demonstrated that it was chiefly in embryology
that precious indications were to be found concerning the genealogy of
organisms.[9] Under the influence of this work, Elie, who until now had
limited himself to introductory researches, resolved to concentrate
all his efforts on the comparative embryology of animals. He started
to work in that direction, and his researches confirmed him more and
more in the opinion that the key of animal evolution and genealogy was
to be sought for in the most primitive stages, in those simple phases
of development where no secondary element has yet been introduced from
external conditions. In those primordial stages, essential characters,
common to all, reveal the analogy and connections between animals from
different groups.
[9] In later years Metchnikoff often dwelt on the fact that Fritz
Müller was not fully appreciated and that it was he who
had most efficaciously contributed to the confirmation of
Darwinian theories.
Every animal begins by being _unicellular_, for the egg-cell, the
reproducing cell, common to all, corresponds to a unicellular being.
It is only after fecundation, when it has become an ovum, that this
first cell evolves by dividing itself into consecutive segments,
each of which is a new cell. This phenomenon is analogous with the
multiplication of unicellular beings through division; only, those
segments of the ovum do not separate but constitute a whole under the
aspect of a hollow sphere, called a _blastula_, which is the first
manifestation of a multicellular being. This blastula is formed of
superposed layers, each of which gives birth to specialised organs in
the embryo. The outside layer, or _ectoderm_, produces teguments and
the nervous system; the internal layer, or _endoderm_, gives birth to
endothelial cells, the digestive and internal organs; between those two
layers comes a third, intermediary layer, the _mesoderm_, from which
the skeleton is developed and also the muscle and blood tissues.
The evolution of these layers in Vertebrates was well known, but very
little so in Invertebrates, though it is only through the development
of inferior forms that the origin and general evolution of living
beings can be elucidated. That is why, during many years, the principal
theme of Metchnikoff's researches was the comparative study of the
embryonic layers of inferior animals and the ulterior fate of their
constituting elements. By following this train of thought, he was able
to demonstrate that the development of lower animals takes place on the
same plan and follows the same laws as that of higher animals; thus,
that there is a real communion between all living beings, which is the
concrete confirmation of the theory of evolution.
By their work, Kovalevsky and Metchnikoff contributed to the foundation
of Comparative Embryology. The comparative study of cells produced
from the divers embryonic layers, and observations on the ulterior
development of the functions of those cells, gradually led Metchnikoff
to his theory of phagocytes and to pathological biology. An
uninterrupted thread can be followed right through his life-work, from
the beginning until the end.
In spite of his absorbing work he took great interest in his
surroundings, and during this first stay in Italy he became acquainted
with two interesting personalities, Bakounine the anarchist and
the celebrated physiologist Setchénoff. Both resided at Sorrento.
Kovalevsky and Metchnikoff, who greatly desired to know them, decided
to call on them, after much hesitation.
Bakounine, a giant with a leonine head and a thick mane of grey hair,
struck them as being a fiery enthusiast but an intolerant sectarian,
easily roused; for instance, any small and unimportant local meeting
was enough for him to predict an imminent revolution in Russia. His
theories were epitomised in these words, "We must not leave stone
upon stone"; but when asked what should be built up on those ruins
he could only say, "We shall see later." Elie looked upon him as a
force powerful by its fire and vitality, but thought his mind neither
judicial nor profound.
Very different was the impression produced on him by Setchénoff.
He carried great weight through the depth of his intelligence, his
persuasive eloquence and general thoroughness. He was of a Mongol
type and his features were plain, but his splendid eyes, deep and
intelligent, shrewd and yet kindly, illumined his face with an
unforgettable inward beauty. When Elie went to see him, it was with the
uneasy feeling that his own knowledge of chemistry and physics was very
restricted, having been very superficially acquired during his rapid
passage through the University. In spite of this cause for bashfulness,
a mental compact and exchange of ideas was immediately established
between the two, and a sympathy was born between them which developed
into a lifelong friendship. Elie expatiated upon his plans for the
study of the embryology of inferior animals from the evolution point
of view, and received from the older scientist much encouragement, for
which he never ceased to be grateful.
He worked a great deal during this first stay at Naples, in spite
of periods of great fatigue. As a relaxation, he plunged into
philosophical reading. After Kovalevsky's departure, he joined
Bakounine's circle, the members of which took their meals in a
restaurant which rejoiced in the sonorous name of _Trattoria della
Harmonia_. In the autumn of the year 1865, a cholera epidemic broke
out in Naples. Every one was nervous and depressed, and this general
depression was increased still more by some of the customs of the
country--continuous lugubrious church bells, funeral processions
in which penitents took part, carrying smoking torches and wearing
hoods over their heads with holes for their eyes, etc. Elie, on whom
the epidemic had made a great impression, was even more disturbed by
the death of one of the members of their little circle, a popular
Englishwoman, liked by everybody. She had no fear of cholera and was
bright and merry. But one day she did not come to the _Trattoria della
Harmonia_; she had been struck by the scourge and was dead the next day.
Elie was so struck by her death that his nerves, already very tense,
gave way and he left Naples, being, moreover, worn out with overwork.
He started for Göttingen, for he wanted to begin the study of
Vertebrates under the direction of Professor Keferstein. Keferstein
straightway gave him a valuable lizard specimen to anatomise. Elie was
not good at technique, on account of his nervous temperament; he used
occasionally to lose his patience and his temper, to that point that he
flung his material across the room. It happened so on this occasion;
having completely wasted the valuable lizard, he conceived a still
greater horror of technique and soon left Professor Keferstein for
Henle, the celebrated anatomist. He worked with him for a short time
at the histology of frogs' kidneys, a subject chosen by the Professor.
Soon the young man realised that he was no longer capable of submitting
to school discipline and resumed his independent researches. When he
had to do with those problems which absorbed him he was always able
to conquer his aversion for technique and to do what was required. He
studied the embryology of the green-fly from the genealogical point
of view, and went to Munich for the summer term in order to work with
the celebrated zoologist von Siebold, a typical and venerable old
German scientist. The latter was too old already to be troubled with
pupils, and Elie studied his insect embryology independently; however,
he visited the old man assiduously, and they had long scientific
conversations. Their relations were always extremely cordial, and they
even kept up a regular correspondence for many years.
During his stay in Germany, music was the young man's only recreation.
He did not play any instrument; his parents, discouraged by the failure
of their elder children, had not had him taught, and besides, his
precocious vocation would have left him no time. Yet he certainly had
a natural talent for music, which he passionately loved. He could
only whistle, but with that feeble means succeeded in reproducing
complicated compositions. Having assiduously attended excellent
concerts, he had made himself thoroughly acquainted with classical
music, and Beethoven and Mozart always remained his favourite
composers. His stay in Germany taught him to appreciate the great
capacity for work of the scientists of that country; he admired the
organisation of their laboratories, allowing every force, great or
small, to be utilised and making useful collective work possible in
those complicated researches which demand the collaboration of divers
specialists. On the other hand, he felt a great aversion for the
manners and customs of German students. Their corporations, duels, and
long sittings in beer-houses were distasteful to him; he could not
understand how these coarse "Burschen" could become transformed into
cultivated intellectuals and respectable scientists. People to whom
he expressed this wonder merely said, "Youth must have its fling...."
Moreover, scientists themselves were not particularly courteous to
each other. More than anywhere else personal questions held a foremost
place, and kindliness was rare between colleagues.
After staying some time in Munich, Elie returned to Naples, war having
broken out between Northern and Southern Germany. This time, in order
to spend less on the journey, he took a steamer at Genoa, but with
fatal results, for a storm was raging; he suffered a great deal, and,
when he reached Naples, violent fits of giddiness made him incapable
of doing any work at all for some time. Cholera reappeared, and the
landlady of the rooms he shared with Kovalevsky died of it. Much
depressed, the two started for Ischia, but Elie soon realised with
terror that he was not yet well enough to work; in order to recover
quickly, he went to Cava, a pretty little place, renowned for its
salubrious climate.
There he met Bakounine again, and they saw a good deal of each other in
a friendly way. Bakounine nicknamed him "Mamma" because of his almost
maternal attentions, a nickname which, for the same reason, was given
him later, quite independently, by other intimates. Yet, though their
relations were cordial and even affectionate, there was not really much
in common between the two. Elie thought Bakounine's ideas superficial,
and disliked his sectarian mentality; they ultimately drifted apart.
His health having gradually recovered owing to the rest, he returned
to Naples in the autumn, after the epidemic had abated, and at last
resumed his work.
Whilst studying the history of the development of Cephalopoda he found
that they had embryonic layers similar to those of Vertebrates; this
was the first time that the fact was established. It was extremely
important, for it constituted a concrete and indisputable proof of
the existence of a genetic connection between inferior and superior
animals. Metchnikoff chose this subject for his thesis, and, having
completed his researches, he returned to Russia in 1867.
By this time he had made great use of his three years' stay abroad.
Though he had not showed himself a docile pupil, yet he had become
initiated into the organisation of scientific work in Germany; he had
carried out independent researches and had been able to choose with
full knowledge the future path of investigations which he was to pursue
for many years in the field of Comparative Embryology.
Already the observations he had made had in themselves a real
importance. For instance, his studies in divers specimens of the worm
type, a type which offers very heterogeneous forms, had permitted him
to establish links of continuity between certain groups among them.
Whilst studying those animals at Giessen in 1865, he had discovered
the capital fact which proved to be the starting-point of all his
future work--the _intercellular digestion_ of an inferior worm, a land
planarian, the _Geodesmus bilineatus_. He had compared this digestion
with that of the superior Infusoria and had seen in it one more proof
of the genetic connection between the type of the Protozoa and that of
worms.
He did not then realise the full bearing of this observation, which
really constituted the basis of his future phagocyte theory; this was
only to appear eighteen years later.
He had also made researches on numerous specimens of insects and on the
scorpion, establishing the fact that they all had embryonic layers;
he concluded that he was "entitled to extend the theory of embryonic
layers to Arthropoda."
Finally, he had discovered embryonic layers similar to those of the
Vertebrates in inferior Invertebrates, the Cephalopoda (Sepiola). This
established a link of continuity between the higher and lower animals.