SUMMARY OF'PHILOSOPHIE ZOOLOGIQUE.' 271 



various phenomena of animal organization, in the mani- 

 fold diversity of its developments, is to be found in the 

 fact that Nature conserves in offspring all that their 

 life and environments has developed in parents." 

 Heredity — "the hidden bond of common descent" — 

 tempered with the modifications induced by changed 

 habits — which changed habits are due to new condi- 

 tions and surroundings — this with Lamarck, as with 

 Buffon and Dr. Darwin, is the explanation of the 

 diversity of forms which we observe in nature. He 

 now goes on to support this-^-briefly, in accordance 

 with his design — but with sufficient detail to prevent 

 all possibility of mistake about his meaning, 



" In the same climate differences in situation, and a 

 greater or less degree of exposure, affect simply, in the 

 first instance, the individuals exposed to them ; , but in 

 the conrse of time, these repeated differences of sur- 

 roundings in individuals which reproduce themselves 

 continually under similar circumstances, induce differ- 

 ences which become part of their very nature ; so that 

 after many successive generations, these individuals, 

 which were originally, we will say, of any given species, 

 become transformed into a different one." * 



" Let us suppose that a grass growing in a low-lying 

 meadow gets carried by some accident to the brow of a 

 neighbouring hill, where the soil is still damp enough 

 for the plant to be able to exist. Let it live here for 

 many generations, till it has become thoroughly accus- 

 tomed to its position, and let it then gradually find its 

 way to the dry and almost arid soil of a mountain side ; 

 • ' Phil. Zool.,' torn. i. pp. 79, 80. 



