180 THE POPULAR SCIENCE MONTHLY. 



a time when there was no life on the earth ; that of the strata some 

 are of marine, some of fresh-water formation ; that they are often in- 

 tercalated like leaves in a book, and therefore cannot be referred to 

 any single cataclysm such as the deluge. 



From considerations connected with the primary rocks, Leibnitz 

 (1680) had inferred that the earth was once at a far higher tempera- 

 ture than now, and in fact must have been in an ignited state ; that 

 it had undergone a gradual cooling. Werner subsequently introduced 

 the Neptunic theory, and Hutton the Plutonic. These cosmographi- 

 cal theories were, however, of less importance than what was clone in 

 paleontology. It was discovered that while similar fossil remains ex- 

 tend over vast horizontal surfaces, different fossils are found to suc- 

 ceed each other very rapidly when a vertical examination is made. 

 There is a geological as well as a geographical distribution of plants 

 and animals geological as to time, geographical as to surface. 



In the works of Maillet (1748), and again in those of Buffon, the 

 old doctrine of evolution reappears. A more formal presentment was, 

 however, made by Lamarck in his " Philosophic zoologique," pub- 

 lished in 1809. He advocated the doctrine of descent, and announced 

 the propositions now known as Darwinism. According to him, organic 

 forms originated by spontaneous generation, the simplest coming first, 

 and the complex being evolved from them. Variations and transmu- 

 tations occur through external influences, the environment modifying 

 the organism, and as these in the lapse of time become essential dif- 

 ferences, new species arise. Moreover, wants experienced cause the 

 will to develop new organs by the modification of previously-existing 

 ones, and these are transmitted by heredity or generation. Organ- 

 isms are developed out of one another; so far from being permanent, 

 they have only a temporary existence. 



Though an organism tends to be like its progenitor, it will undergo 

 changes by the use or disuse of its parts ; by the former it is devel- 

 oped, by the latter deteriorated. The changes produced thus, or by 

 the environment, always have been, and always will be, continuous, 

 not catastrophic. 



Lamarck recognized the struggle of each against all. He saw 

 plainly the influence of heredity, and understood the relation of envi- 

 ronment and adaptation. He defined in the clearest manner the doc- 

 trine of transmutation and theory of descent. According to him, if 

 time enough be allowed, any modification may take place. 



So far from meeting with acceptance, the ideas of Lamarck brought 

 upon him ridicule and obloquy. He was as much misrepresented as 

 in former times the Arabian Nature-philosophers had been. The great 

 influence of Cuvier, who had made himself a champion of the doctrine 

 of permanence of species, caused Lamarck's views to be silently ig- 

 nored, or, if by chance they were referred to, denounced. They were 



