LAMARCK THE ZOÖLOGIST
Although there has been and still may be a difference of opinion as to
the value and permanency of Lamarck's theoretical views, there has never
been any lack of appreciation of his labors as a systematic zoölogist.
He was undoubtedly the greatest zoölogist of his time. Lamarck is the
one dominant personage who in the domain of zoölogy filled the interval
between Linné and Cuvier, and in acuteness and sound judgment he at
times surpassed Cuvier. His was the master mind of the period of
systematic zoölogy, which began with Linné--the period which, in the
history of zoölogy, preceded that of comparative anatomy and morphology.
After Aristotle, no epoch-making zoölogist arose until Linné was born.
In England Linné was preceded by Ray, but binomial nomenclature and the
first genuine attempt at the classification of animals dates back to the
_Systema Naturæ_ of Linné, the tenth edition of which appeared in 1758.
[Illustration: PORTRAIT OF LAMARCK]
The contemporaries of Lamarck in biological science, in the eighteenth
century, were Camper (1722-89), Spallanzani (1729-99), Wolff (1733-94),
Hunter (1728-93), Bichat (1771-1802), and Vicq d'Azyr (1748-94). These
were all anatomists and physiologists, the last-named being the first
to propose and use the term "comparative anatomy," while Bichat was the
founder of histology and pathological anatomy. There was in fact no
prominent systematic zoölogist in the interval between Linné and
Lamarck. In France there were only two zoölogists of prominence when
Lamarck assumed his duties at the Museum. These were Bruguière the
conchologist and Olivier the entomologist. In Germany Hermann was the
leading systematic zoölogist. We would not forget the labors of the
great German anatomist and physiologist Blumenbach, who was also the
founder of anthropology; nor the German anatomists Tiedemann, Bojanus,
and Carus; nor the embryologist Döllinger. But Lamarck's method and
point of view were of a new order--he was much more than a mere
systematist. His work in systematic zoölogy, unlike that of Linné, and
especially of Cuvier, was that of a far higher grade. Lamarck, besides
his rigid, analytical, thorough, and comprehensive work on the
invertebrates, whereby he evolved order and system out of the chaotic
mass of forms comprised in the Insects and Vermes of Linné, was animated
with conceptions and theories to which his forerunners and
contemporaries, Geoffroy St. Hilaire excepted, were entire strangers.
His tabular view of the classes of the animal kingdom was to his mind a
genealogical tree; his idea of the animal kingdom anticipated and was
akin to that of our day. He compares the animal series to a tree with
its numerous branches, rather than to a single chain of being. This
series, as he expressly states, began with the monad and ended with
man; it began with the simple and ended with the complex, or, as we
should now say, it proceeded from the generalized or undifferentiated to
the specialized and differentiated. He perceived that many forms had
been subjected to what he calls degeneration, or, as we say,
modification, and that the progress from the simple to the complex was
by no means direct. Moreover, fossil animals were, according to his
views, practically extinct species, and stood in the light of being the
ancestors of the members of our existing fauna. In fact, his views,
notwithstanding shortcomings and errors in classification naturally due
to the limited knowledge of anatomy and development of his time, have
been at the end of a century entirely confirmed--a striking testimony to
his profound insight, sound judgment, and philosophic breadth.
The reforms that he brought about in the classification of the
invertebrate animals were direct and positive improvements, were adopted
by Cuvier in his _Règne animal_, and have never been set aside. We owe
to him the foundation and definition of the classes of Infusoria,
Annelida, Arachnida, and Crustacea, the two latter groups being
separated from the insects. He also showed the distinctness of
echinoderms from polyps, thus anticipating Leuckart, who established the
phylum of Coelenterata nearly half a century later. His special work
was the classification of the great group of Mollusca, which he regarded
as a class. When in our boyhood days we attempted to arrange our shells,
we were taught to use the Lamarckian system, that of Linné having been
discarded many years previous. The great reforms in the classification
of shells are evidenced by the numerous manuals of conchology based on
the works of Lamarck.
We used to hear much of the Lamarckian genera of shells, and Lamarck was
the first to perceive the necessity of breaking up into smaller
categories the few genera of Linné, which now are regarded as families.
He may be said to have had a wonderfully good eye for genera. All his
generic divisions were at once accepted, since they were based on valid
characters.
Though not a comparative anatomist, he at once perceived the value of a
knowledge of the internal structure of animals, and made effective use
of the discoveries of Cuvier and of his predecessors--in fact, basing
his system of classification on the organs of respiration, circulation,
and the nervous system.
He intimated that specific characters vary most, and that the peripheral
parts of the body, as the shell, outer protective structures, the limbs,
mouth-parts, antennæ, etc., are first affected by the causes which
produce variation, while he distinctly states that it requires a longer
time for variations to take place in the internal organs. On the latter
he relied in defining his classes.
One is curious to know how Lamarck viewed the question of species. This
is discussed at length by him in his general essays, which are
reproduced farther on in this biography, but his definition of what a
species is far surpasses in breadth and terseness, and better satisfies
the views now prevailing, than that of any other author.
His definition of a species is as follows:
"Every collection of similar individuals, perpetuated by generation
in the same condition, so long as the circumstances of their
situation do not change enough to produce variations in their
habits, character, and form."
Lamarck's rare skill, thoroughness, and acuteness as an observer,
combined with great breadth of view, were also supplemented by the
advantages arising from residence in Paris, and his connection with the
Museum of Natural History. Paris was in the opening years of the
nineteenth century the chief centre of biological science. France having
convalesced from the intestinal disorders of the Revolution, and, as the
result of her foreign wars, adding to her territory and power, had begun
with the strength of a young giant to send out those splendid exploring
expeditions which gathered in collections in natural history from all
parts of the known or accessible world, and poured them, as it were,
into the laps of the professors of the Jardin des Plantes. The shelves
and cases of the galleries fairly groaned with the weight of the
zoölogical riches which crowded them. From the year 1800 to 1832 the
French government showed the greatest activity in sending out exploring
expeditions to Egypt, Africa, and the tropics.[119]
The zoölogists who explored Egypt were Geoffroy St. Hilaire and Savigny.
Those who visited the East, the South Seas, the East Indian archipelago,
and other regions were Bruguière, Olivier, Bory de St. Vincent, Péron,
Lesueur, Quoy, Gaimard, Le Vaillant, Edoux, and Souleyet. The natural
result was the enormous collections of the Jardin des Plantes, and
consequently enlarged views regarding the number and distribution of
species, and their relation to their environment.
In Paris, about the time of Lamarck's death, flourished also Savigny,
who published his immortal works on the morphology of arthropods and of
ascidians; and Straus-Durckheim, whose splendidly illustrated volumes on
the anatomy of the cockchafer and of the cat will never cease to be of
value; and É. Geoffroy St. Hilaire, whose elaborate and classical works
on vertebrate morphology, embryology, and comparative anatomy added so
much to the prestige of French science.
We may be sure that Lamarck did his own work without help from others,
and gave full credit to those who, like Defrance or Bruguière, aided or
immediately preceded him. He probably was lacking in executive force, or
in the art which Cuvier knew so well to practise, of enlisting young men
to do the drudgery or render material aid, and then, in some cases,
neglecting to give them proper credit.
The first memoir or paper published on a zoölogical subject by Lamarck
was a modest one on shells, which appeared in 1792 in the _Journal
d'Histoire naturelle_, the editors of which were Lamarck, Bruguière,
Olivier, Haüy, and Pelletier. This paper was a review of an excellent
memoir by Bruguière, who preceded Lamarck in the work of dismemberment
of the Linnæan genera. His next paper was on four new species of Helix.
To this _Journal_, of which only two volumes were published, Cuvier
contributed his first paper--namely, on some new species of "Cloportes"
(Oniscus, a genus of terrestrial crustacea or "pill-bugs"); this was
followed by his second memoir on the anatomy of the limpet, his next
article being descriptions of two species of flies from his collection
of insects.[120] Seven years later Lamarck gave some account of the
genera of cuttlefishes. His first general memoir was a prodromus of a
new classification of shells (1799).
Meanwhile Lamarck's knowledge of shells and corals was utilized by
Cuvier in his _Tableau élémentaire_, published in 1798, who acknowledges
in the preface that in the exposition of the genera of shells he has
been powerfully seconded, while he indicated to him (Cuvier) a part of
the subgenera of corals and alcyonarians, and adds, "I have received
great aid from the examination of his collection." Also he acknowledges
that he had been greatly aided (_puissamment secondé_) by Lamarck, who
had even indicated the most of the subdivisions established in his
_Tableau élémentaire_ for the insects (Blainville, _l. c._, p. 129), and
he also accepted his genera of cuttlefishes.
After this Lamarck judiciously refrained from publishing descriptions of
new species, and other fragmentary labors, and for some ten years from
the date of publication of his first zoölogical article reserved his
strength and elaborated his first general zoölogical work, a thick
octavo volume of 452 pages, entitled _Système des Animaux sans
Vertèbres_, which appeared in 1801.
Linné had divided all the animals below the vertebrates into two classes
only, the Insecta and Vermes, the insects comprising the present classes
of insects, Myriapoda, Arachnida, and Crustacea; the Vermes embracing
all the other invertebrate animals, from the molluscs to the monads.
Lamarck perceived the need of reform, of bringing order out of the
chaotic mass of animal forms, and he says (p. 33) that he has been
continually occupied since his attachment to the museum with this
reform.
He relies for his characters, the fundamental ones, on the organs of
respiration, circulation, and on the form of the nervous system. The
reasons he gives for his classification are sound and philosophical, and
presented with the ease and aplomb of a master of taxonomy.
He divided the invertebrates, which Cuvier had called animals with white
blood, into the seven following classes.
We place in a parallel column the classification of Cuvier in 1798.
_Classification of Lamarck._ _Classification of Cuvier._
1. Mollusca. I. _Mollusca._
2. Crustacea. II. _Insectes et Vers._
3. Arachnides (comprising 1. Insectes.
the Myriapoda). 2. Vers.
4. Insectes. III. _Zoophytes._
5. Vers. 1. Echinodermes.
2. Meduses, Animaux
6. Radiaires. infusorines, Rotifer,
Vibrio, Volvox.
7. Polypes. 3. Zoophytes proprement
dits.
Of these, four were for the first time defined, and the others
restricted. It will be noticed that he separates the Radiata
(_Radiaires_) from the Polypes. His "Radiaires" included the
Echinoderms (the _Vers echinoderms_ of Bruguière) and the Medusæ (his
_Radiaires molasses_), the latter forming the Discophora and
Siphonophora of present zoölogists. This is an anticipation of the
division by Leuckart in 1839 of the Radiata of Cuvier into
Coelenterata and Echinodermata.
The "Polypes" of Lamarck included not only the forms now known as such,
but also the Rotifera and Protozoa, though, as we shall see, he
afterwards in his course of 1807 eliminated from this heterogeneous
assemblage the Infusoria.
Comparing this classification with that of Cuvier[121] published in
1798, we find that in the most important respects, _i.e._, the
foundation of the classes of Crustacea, Arachnida, and Radiata, there is
a great advance over Cuvier's system. In Cuvier's work the molluscs are
separated from the worms, and they are divided into three groups,
Cephalopodes, Gasteropodes, and Acephales--an arrangement which still
holds, that of Lamarck into Mollusques céphalés and Mollusques acéphalés
being much less natural. With the elimination of the Mollusca, Cuvier
allowed the Vers or Vermes of Linné to remain undisturbed, except that
the Zoöphytes, the equivalent of Lamarck's Polypes, are separately
treated.
He agrees with Cuvier in placing the molluscs at the head of the
invertebrates, a course still pursued by some zoölogists at the present
day. He states in the _Philosophie Zoologique_[122] that in his course
of lectures of the year 1799 he established the class of Crustacea, and
adds that "although this class is essentially distinct, it was not until
six or seven years after that some naturalists consented to adopt it."
The year following, or in his course of 1800, he separated from the
insects the class of Arachnida, as "easy and necessary to be
distinguished." But in 1809 he says that this class "is not yet admitted
into any other work than my own."[123] As to the class of Annelides, he
remarks: "Cuvier having discovered the existence of arterial and venous
vessels in different animals which have been confounded under the name
of worms (_Vers_) with other animals very differently organized, I
immediately employed the consideration of this new fact in rendering my
classification more perfect, and in my course of the year 10 (1802) I
established the class of Annelides, a class which I have placed after
the molluscs and before the crustaceans, as their known organization
requires." He first established this class in his _Recherches sur les
corps vivans_ (1802), but it was several years before it was adopted by
naturalists.
The next work in which Lamarck deals with the classification of the
invertebrates is his _Discours d'ouverture du Cours des Animaux sans
Vertèbres_, published in 1806.
On page 70 he speaks of the animal chain or series, from the monad to
man, ascending from the most simple to the most complex. The monad is
one of his _Polypes amorphs_, and he says that it is the most simple
animal form, the most like the original germ (_ébauche_) from which
living bodies have descended. From the monad nature passes to the
Volvox, Proteus (Amoeba), and Vibrio. From them are derived the
_Polypes rotifères_ and other "Radiaires," and then the Vers,
Arachnides, and Crustacea. On page 77 a tabular view is presented, as
follows:
1. _Les Mollusques._
2. _Les Cirrhipèdes._
3. _Les Annelides._
4. _Les Crustacés._
5. _Les Arachnides._
6. _Les Insectes._
7. _Les Vers._
8. _Les Radiaires._
9. _Les Polypes._
It will be seen that at this date two additional classes are proposed
and defined--_i.e._, the Annelides and the Cirrhipedes, though the class
of Annelida was first privately characterized in his lectures for 1802.
The elimination of the barnacles or Cirrhipedes from the molluscs was a
decided step in advance, and was a proof of the acute observation and
sound judgment of Lamarck. He says that this class is still very
imperfectly known and its position doubtful, and adds: "The Cirrhipedes
have up to the present time been placed among the molluscs, but
although certain of them closely approach them in some respects, they
have a special character which compels us to separate them. In short, in
the genera best known the feet of these animals are distinctly
articulated and even crustaceous (_crustacés_)." He does not refer to
the nervous system, but this is done in his next work. It will be
remembered that Cuvier overlooked this feature of the jointed limbs, and
also the crustaceous-like nervous system of the barnacles, and allowed
them to remain among the molluscs, notwithstanding the decisive step
taken by Lamarck. It was not until many years after (1830) that Thompson
proved by their life-history that barnacles are true crustacea.
In the _Philosophie zoologique_ the ten classes of the invertebrates are
arranged in the following order:
_Les Mollusques._
_Les Cirrhipèdes._
_Les Annelides._
_Les Crustacés._
_Les Arachnides._
_Les Insectes._
_Les Vers._
_Les Radiaires._
_Les Polypes._
_Les Infusoires._
At the end of the second volume Lamarck gives a tabular view on a page
by itself (p. 463), showing his conception of the origin of the
different groups of animals. This is the first phylogeny or genealogical
tree ever published.
TABLEAU
Servant à montrer l'origine des differens animaux.
Vers. Infusoires.
. Polypes.
. Radiaires.
.
. .
. .
. .
. Insectes.
. Arachnides.
Annelides. Crustacés.
Cirrhipèdes.
Mollusques.
.
.
.
Poissons.
Reptiles.
.
. .
. .
Oiseaux. .
. .
. .
Monotrèmes. M. Amphibies.
.
. .
. .
. . M. Cétacés.
. .
. M. Ongulés.
M. Onguiculés.
The next innovation made by Lamarck in the _Extrait du Cours de
Zoologie_, in 1812, was not a happy one. In this work he distributed the
fourteen classes of the animal kingdom into three groups, which he named
_Animaux Apathiques_, _Sensibles_, and _Intelligens_. In this
physiologico-psychological base for a classification he unwisely
departed from his usual more solid foundation of anatomical structure,
and the results were worthless. He, however, repeats it in his great
work, _Histoire naturelle des Animaux sans Vertèbres_ (1815-1822).
The sponges were by Cuvier, and also by Lamarck, accorded a position
among the Polypes, near Alcyonium, which represents the latter's
_Polypiers empâtés_; and it is interesting to notice that, for many
years remaining among the Protozoa, meanwhile even by Agassiz regarded
as vegetables, they were by Haeckel restored to a position among the
Coelenterates, though for over twenty years they have by some American
zoölogists been more correctly regarded as a separate phylum.[124]
Lamarck also separated the seals and morses from the cetacea. Adopting
his idea, Cuvier referred the seals to an order of carnivora.
Another interesting matter, to which Professor Lacaze-Duthiers has
called attention in his interesting letter on p. 77, is the position
assigned _Lucernaria_ among his _Radiaires molasses_ near what are now
Ctenophora and Medusæ, though one would have supposed he would, from
its superficial resemblance to polyps, have placed it among the polyps.
To Lamarck we are also indebted for the establishment in 1818 of the
molluscan group of Heteropoda.
Lamarck's acuteness is also shown in the fact that, whereas Cuvier
placed them among the acephalous molluscs, he did not regard the
ascidians as molluscs at all, but places them in a class by themselves
under the name of _Tunicata_, following the Sipunculus worms. Yet he
allowed them to remain near the Holothurians (then including Sipunculus)
in his group of _Radiaires echinodermes_, between the latter and the
Vers. He differs from Cuvier in regarding the tunic as the homologue of
the shell of Lamellibranches, remarking that it differs in being
muscular and contractile.
Lamarck's fame as a zoölogist rests chiefly on this great work. It
elicited the highest praise from his contemporaries. Besides containing
the innovations made in the classification of the animal kingdom, which
he had published in previous works, it was a summary of all which was
then known of the invertebrate classes, thus forming a most convenient
hand-book, since it mentioned all the known genera and all the known
species except those of the insects, of which only the types are
mentioned. It passed through two editions, and still is not without
value to the working systematist.
In his _Histoire des Progrès des Sciences naturelles_ Cuvier does it
justice. Referring to the earlier volume, he states that "it has
extended immensely the knowledge, especially by a new distribution, of
the shelled molluscs ... M. de Lamarck has established with as much
care as sagacity the genera of shells." Again he says, in noticing the
three first volumes: "The great detail into which M. de Lamarck has
entered, the new species he has described, renders his work very
valuable to naturalists, and renders most desirable its prompt
continuation, especially from the knowledge we have of means which this
experienced professor possesses to carry to a high degree of perfection
the enumeration which he will give us of the shells" (_Oeuvres
complètes de Buffon_, 1828, t. 31, p. 354).
"His excellences," says Cleland, speaking of Lamarck as a scientific
observer, "were width of scope, fertility of ideas, and a preëminent
faculty of precise description, arising not only from a singularly terse
style, but from a clear insight into both the distinctive features and
the resemblance of forms" (_Encyc. Britannica_, Art. LAMARCK).
The work, moreover, is remarkable for being the first one to begin with
the simplest and to end with the most highly developed forms.
Lamarck's special line of study was the Mollusca. How his work is still
regarded by malacologists is shown by the following letter from our
leading student of molluscs, Dr. W. H. Dall:
"SMITHSONIAN INSTITUTION,
"UNITED STATES NATIONAL MUSEUM, WASHINGTON, D. C.,
"_November 4, 1899._
"Lamarck was one of the best naturalists of his time, when geniuses
abounded. His work was the first well-marked step toward a natural
system as opposed to the formalities of Linné. He owed something to
Cuvier, yet he knew how to utilize the work in anatomy offered by
Cuvier in making a natural classification. His failing eyesight,
which obliged him latterly to trust to the eyes of others; his
poverty and trials of various kinds, more than excuse the occasional
slips which we find in some of the later volumes of the _Animaux
sans Vertèbres_. These are rather of the character of typographical
errors than faults of scheme or principle.
"The work of Lamarck is really the foundation of rational natural
malacological classification; practically all that came before his
time was artificial in comparison. Work that came later was in the
line of expansion and elaboration of Lamarck's, without any change
of principle. Only with the application of embryology and
microscopical work of the most modern type has there come any
essential change of method, and this is rather a new method of
getting at the facts than any fundamental change in the way of using
them when found. I shall await your work on Lamarck's biography with
great interest.
"I remain,
"Yours sincerely,
"WILLIAM H. DALL."
FOOTNOTES:
[119] During the same period (1803-1829) Russia sent out expeditions to
the North and Northeast, accompanied by the zoölogists Tilesius,
Langsdorff, Chamisso, Eschscholtz, and Brandt, all of them of German
birth and education. From 1823 to 1850 England fitted up and sent out
exploring expeditions commanded by Beechey, Fitzroy, Belcher, Ross,
Franklin, and Stanley, the naturalists of which were Bennett, Owen,
Darwin, Adams, and Huxley. From Germany, less of a maritime country, at
a later date, Humboldt, Spix, Prince Wied-Neuwied, Natterer, Perty, and
others made memorable exploring expeditions and journeys.
[120] These papers have been mercilessly criticised by Blainville in his
"Cuvier et Geoffroy St. Hilaire." In the second article--_i.e._, on the
anatomy of the limpet--Cuvier, in considering the organs, follows no
definite plan; he gives a description "_tout-a-fait fantastique_" of the
muscular fibres of the foot, and among other errors in this first essay
on comparative anatomy he mistakes the tongue for the intromittent
organ; the salivary glands, and what is probably part of the brain,
being regarded as the testes, with other "_erreurs matérielles
inconcevables, même à l'époque ou elle fut rédigée_." In his first
article he mistakes a species of the myriapod genus Glomeris for the
isopod genus Armadillo. In this he is corrected by the editor (possibly
Lamarck himself), who remarks in a footnote that the forms to which
M. Cuvier refers under the name of Armadillo are veritable species of
Julus. We have verified these criticisms of Cuvier by reference to his
papers in the "Journal." It is of interest to note, as Blainville does,
that Cuvier at this period admits that there is a passage from the
Isopoda to the armadilloes and Julus. Cuvier, then twenty-three years
old, wrote: "_Nous sommes donc descendus par degrès, des Écrevisses aux
Squilles, de celles-ci aux Aselles, puis aux Cloportes, aux Armadilles
et aux Ïules_" (_Journal d'Hist. nat._, tom. ii., p. 29, 1792). These
errors, as regards the limpet, were afterwards corrected by Cuvier
(though he does not refer to his original papers) in his _Mémoires pour
servir à l'Histoire et à l'Anatomie des Mollusques_ (1817).
[121] _Tableau élémentaire de l'Histoire naturelle des Animaux._ Paris,
An VI. (1798). 8vo, pp. 710. With 14 plates.
[122] Tome i., p. 123.
[123] In his _Histoire des Progrès des Sciences naturelles_ Cuvier takes
to himself part of the credit of founding the class Crustacea, stating
that Aristotle had already placed them in a class by themselves, and
adding, "_MM. Cuvier et de Lamarck les en out distingués par des
caractères de premier ordre tirés de leur circulation._" Undoubtedly
Cuvier described the circulation, but it was Lamarck who actually
realized the taxonomic importance of this feature and placed them in a
distinct class.
[124] See A. Hyatt's _Revision of North American Poriferæ_, Part II.
(Boston, 1877, p. 11); also the present writer in his _Text-book of
Zoölogy_ (1878).