MODERN BIOLOGY 315 



man-apes. Possibly, too, fears of censure on the part of the Napoleonic 

 Government had their influence in this respect. 



After a brief discussion of the term "species" in the vegetable and animal 

 kingdoms in relation to the mineral kingdom, wherein he states that the 

 mineral differs from plants and animals in not possessing individuality, and 

 further emphasizes the influence of environment upon the development of 

 species, adducing such examples as the deep-water and shore form of Ranun- 

 culus aquaticus, Lamarck proceeds to record his views on the nervous system 

 and its functions. As he deals with the same subject more fully in his sub- 

 sequent works, we may postpone our account of his views on these questions 

 and here close our resume of his Kechercbes — the work that displays his genius 

 and his limitations more clearly, perhaps, than any other. 



In his Philosophic xpologique Lamarck discusses once more his theory of 

 the development of life in nature. By way of introduction he examines the 

 question of how much is human invention and how much is nature's own 

 law in natural science, and he comes to the conclusion, with Buffon, that all 

 systematic classifications are arbitrary products of human thought; in nature 

 there are only individuals, which can certainly be placed in groups in respect 

 of certain characteristics, but the lines between which are always arbitrarily 

 drawn. As regards the problem of evolution itself, he adopts the same plan 

 as in Kechercbes; he first describes the "degradation" throughout the animal 

 kingdom, and then expounds the theory as to how the organs, and therewith 

 the animal forms themselves, have developed by habit and way of living. 

 He further insists upon the importance of the essential organs for purposes 

 of development in contrast to the non-essential, citing the old instances of 

 how organs develop, to which reference has been made above, and a number 

 of new ones besides — sometimes quite absurd ideas, such as that the males 

 of the Ruminantia have acquired horns through the blood having gone to 

 their heads in the mating-season. In regard to the general conditions under 

 which life has developed, he holds that the earth has evolved continuously 

 and not as a result of catastrophes, as Buffon, and after him Cuvier, main- 

 tained, and also that no animal species have died out, except those that man 

 himself has eradicated, but that the fossil species that are not found at the 

 present time have been transformed into now existing forms. With increased 

 emphasis and with his criticism directed especially against Cuvier, he seeks 

 to prove that all animal classes are derived from one another and should 

 therefore be arranged in a line and not parallel or "reticularly"; nevertheless, 

 it is permitted for the genera in each class to form ramifications from a 

 common primal form. Further, in a supplement to the work he extends this 

 ramification theory to the classes in the Vertebrata, in that the birds are 

 derived from the tortoises and the mammals from the crocodiles. 



