298 EVOLUTION, OLD AND NEW . 



" The modifications of ammals arise more slowly than 

 those of plants ; they are therefore less easily watched, 

 and less easily assignable to their true causes, but they 

 arise none the less surely. As regards these causes, the 

 most potent is diversity of the surroundings in which 

 they exist, but there are also many others.* 



"The climate of the same place changes, and the 

 place itself changes with changed climate and'exposure, 

 but so slowly that we imagine all lands to be stable in 

 their conditions. This, however, is not true ; climatic 

 and other changes induce corresponding changes in 

 environment and habit, and these modify the structure 

 of the living forms which are subjected to them. In- 

 deed, we see intermediate forms and species corre- 

 sponding to intermediate conditions. 



" To the above causes must be ascribed the infinite 

 variety of existing forms, independently of any tendency 

 towards progressive development." t 



The reader has now before him a fair sample of " the 

 well-known doctrine of inherited habit as advanced by 

 Lamarck." % In what way, let me ask in passing, does 

 "the case of neuter insects" prove "demonstrative" 

 against it, unless it is held equally demonstrative 

 against Mr. Darwin's own position? Lamarck con- 

 tinues : — 



" The character of any habitable quarter of the globe 

 is qua man constant : the constancy of type in species 

 is therefore also qua man persistent. But this id an 



• ' Phil. Zool.,' torn. i. p. 232. 



t Page 233. See Buffon on Climate, torn, ix., ' The Ammals of the 

 Old and New Worlds.' 

 X ' Origin of Species,' p. 233, ed. 1876. 



