442 PALEONTOLOGY. 



the species of higher organisms, distinguishable as plants and 

 animals, their origin is as yet only matter of speculation. 



Buffon * regarded varieties as particular alterations of 

 species, which illustrated the mutability of species themselves. 

 He held that most of the so-called species in the Linnsean 

 system were but so many evidences of the progressive degrees 

 of change which had been superinduced by time and successive 

 generations, and chiefly by degradation from a primordial type. 

 Applying this principle to the quadrupeds of which he had 

 given the history in his great work, he believed himself able 

 to reduce them, with the exception of a few insulated forms, 

 to a very small number of primitive stocks, of which he 

 enumerates " fifteen." 



Mr. Darwin, in the work above cited, is led to believe that 

 " animals have descended from at most only four or five pro- 

 genitors, and plants from an equal or lesser number. Ana- 

 logy," he adds, " would lead me one step further, namely, to the 

 belief that all animals and plants have descended from some one 

 primordial form, into which life was first breathed" (p. 414). 



Lamarck f rejects even this limitation of the supernatural 

 act whereby " certain elemental atoms had been commanded 

 suddenly to flash into living tissues" (Darwin, p. 483); and with 

 a more consistent trust in the potentiality of second causes, he 

 conceives that the simplest single-celled organisms are ever in 

 course of being formed out of their elemental atoms. These 

 stand in the place of Darwin's primordial created forms. The 

 progress of transmutation and development is onwards, in a 

 direction the reverse of Buffon's. Adverting to observed 

 ranges of variation in certain species, Lamarck affirms that such 

 variations proceed and keep pace with the continued operation 

 of the causes producing them ; that such changes of form and 

 structure induce corresponding changes in actions, and that a 



* Histoire Naturelle, Degeneration des Animaux, torn, xiv., p. 311. 

 + " Philosophic Zoologique," 8vo., 1809. 



