Lamarck, the Founder of Evolution Part 16

"In 1785 (_Hist. de l'Acad._) he evinced his appreciation of the necessity of natural orders in botany by an attempt at the cla.s.sification of plants, interesting though crude, and falling immeasurably short of the system which grew in the hands of his intimate friend Jussieu."--_Encyc. Brit._, Art. LAMARCK.

A genus of tropical plants of the group _Solanaceae_ was named _Markea_ by Richard, in honor of Lamarck, but changed by Persoon and Poiret to _Lamarckea_. The name _Lamarckia_ of Moench and Koeler was proposed for a genus of gra.s.ses; it is now _Chrysurus_.

Lamarck's success as a botanist led to more or less intimate relations with Buffon. But it appears that the good-will of this great naturalist and courtier for the rising botanist was not wholly disinterested.

Lamarck owed the humble and poorly paid position of keeper of the herbarium to Buffon. Bourguin adds, however:

"_Mais il les dut moins a ses merites qu'aux pet.i.ts pa.s.sions de la science officielle._ The ill.u.s.trious Buffon, who was at the same time a very great lord at court, was jealous of Linne. He could not endure having any one compare his brilliant and eloquent word-pictures of animals with the cold and methodical descriptions of the celebrated Swedish naturalist. So he attempted to combat him in another field--botany. For this reason he encouraged and pushed Lamarck into notice, who, as the popularizer of the system of cla.s.sification into natural families, seemed to him to oppose the development of the arrangement of Linne."

Lamarck's style was never a highly finished one, and his incipient essays seemed faulty to Buffon, who took so much pains to write all his works in elegant and pure French. So he begged the Abbe Hauy to review the literary form of Lamarck's works.

Here it might be said that Lamarck's is the philosophic style; often animated, clear, and pure, it at times, however, becomes prolix and tedious, owing to occasional repet.i.tion.

But after all it can easily be understood that the discipline of his botanical studies, the friends.h.i.+p manifested for him by Buffon, then so influential and popular, the relations Lamarck had with Jussieu, Hauy, and the zoologists of the Jardin du Roi, were all important factors in Lamarck's success in life, a success not without terrible drawbacks, and to the full fruition of which he did not in his own life attain.

CHAPTER XII

LAMARCK THE ZOoLOGIST

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 zoologist.

He was undoubtedly the greatest zoologist of his time. Lamarck is the one dominant personage who in the domain of zoology filled the interval between Linne and Cuvier, and in acuteness and sound judgment he at times surpa.s.sed Cuvier. His was the master mind of the period of systematic zoology, which began with Linne--the period which, in the history of zoology, preceded that of comparative anatomy and morphology.

After Aristotle, no epoch-making zoologist arose until Linne was born.

In England Linne was preceded by Ray, but binomial nomenclature and the first genuine attempt at the cla.s.sification of animals dates back to the _Systema Naturae_ of Linne, the tenth edition of which appeared in 1758.

[Ill.u.s.tration: 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), b.i.+.c.hat (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 b.i.+.c.hat was the founder of histology and pathological anatomy. There was in fact no prominent systematic zoologist in the interval between Linne and Lamarck. In France there were only two zoologists of prominence when Lamarck a.s.sumed his duties at the Museum. These were Bruguiere the conchologist and Olivier the entomologist. In Germany Hermann was the leading systematic zoologist. 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, Boja.n.u.s, and Carus; nor the embryologist Dollinger. 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 zoology, unlike that of Linne, and especially of Cuvier, was that of a far higher grade. Lamarck, besides his rigid, a.n.a.lytical, thorough, and comprehensive work on the invertebrates, whereby he evolved order and system out of the chaotic ma.s.s of forms comprised in the Insects and Vermes of Linne, was animated with conceptions and theories to which his forerunners and contemporaries, Geoffroy St. Hilaire excepted, were entire strangers.

His tabular view of the cla.s.ses of the animal kingdom was to his mind a genealogical tree; his idea of the animal kingdom antic.i.p.ated 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 cla.s.sification 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 cla.s.sification of the invertebrate animals were direct and positive improvements, were adopted by Cuvier in his _Regne animal_, and have never been set aside. We owe to him the foundation and definition of the cla.s.ses 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 antic.i.p.ating Leuckart, who established the phylum of Coelenterata nearly half a century later. His special work was the cla.s.sification of the great group of Mollusca, which he regarded as a cla.s.s. When in our boyhood days we attempted to arrange our sh.e.l.ls, we were taught to use the Lamarckian system, that of Linne having been discarded many years previous. The great reforms in the cla.s.sification of sh.e.l.ls are evidenced by the numerous manuals of conchology based on the works of Lamarck.

We used to hear much of the Lamarckian genera of sh.e.l.ls, and Lamarck was the first to perceive the necessity of breaking up into smaller categories the few genera of Linne, 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 cla.s.sification 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 sh.e.l.l, outer protective structures, the limbs, mouth-parts, antennae, 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 cla.s.ses.

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 surpa.s.ses 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 circ.u.mstances 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 zoological 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 zoologists 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 Bruguiere, Olivier, Bory de St. Vincent, Peron, 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 ill.u.s.trated volumes on the anatomy of the c.o.c.kchafer and of the cat will never cease to be of value; and e. Geoffroy St. Hilaire, whose elaborate and cla.s.sical 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 Bruguiere, 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 zoological subject by Lamarck was a modest one on sh.e.l.ls, which appeared in 1792 in the _Journal d'Histoire naturelle_, the editors of which were Lamarck, Bruguiere, Olivier, Hauy, and Pelletier. This paper was a review of an excellent memoir by Bruguiere, who preceded Lamarck in the work of dismemberment of the Linnaean 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 cla.s.sification of sh.e.l.ls (1799).

Meanwhile Lamarck's knowledge of sh.e.l.ls and corals was utilized by Cuvier in his _Tableau elementaire_, published in 1798, who acknowledges in the preface that in the exposition of the genera of sh.e.l.ls 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 seconde_) by Lamarck, who had even indicated the most of the subdivisions established in his _Tableau elementaire_ for the insects (Blainville, _l. c._, p. 129), and he also accepted his genera of cuttlefishes.

After this Lamarck judiciously refrained from publis.h.i.+ng descriptions of new species, and other fragmentary labors, and for some ten years from the date of publication of his first zoological article reserved his strength and elaborated his first general zoological work, a thick octavo volume of 452 pages, ent.i.tled _Systeme des Animaux sans Vertebres_, which appeared in 1801.

Linne had divided all the animals below the vertebrates into two cla.s.ses only, the Insecta and Vermes, the insects comprising the present cla.s.ses 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 ma.s.s 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 cla.s.sification 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 cla.s.ses.

We place in a parallel column the cla.s.sification of Cuvier in 1798.

_Cla.s.sification of Lamarck._ _Cla.s.sification 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 Bruguiere) and the Medusae (his _Radiaires mola.s.ses_), the latter forming the Discophora and Siphonophora of present zoologists. This is an antic.i.p.ation 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 a.s.semblage the Infusoria.

Comparing this cla.s.sification with that of Cuvier[121] published in 1798, we find that in the most important respects, _i.e._, the foundation of the cla.s.ses 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 cephales and Mollusques acephales being much less natural. With the elimination of the Mollusca, Cuvier allowed the Vers or Vermes of Linne to remain undisturbed, except that the Zoophytes, the equivalent of Lamarck's Polypes, are separately treated.