378 OUTLINES OF EVOLUTIONARY BIOLOGY 



complete want of employment of this part has caused it to 

 gradually cease from developing like the other parts of the 

 animal ; that it has become reduced and attenuated little by 

 little, and that at length, when this want of employment has 

 been complete during a long period, the part in question has in 

 the end disappeared. All this is positive ; I propose to give the 

 most convincing proofs of it. 



"In plants, where there are no actions, and consequently no 

 habits properly so-called, great changes in the environment have 

 none the less led to great differences in the development of their 

 parts ; in such a way that these differences have caused certain 

 of them to appear and develop, while they have caused many 

 others to dwindle away and disappear. B;it here everything is 

 effected by changes which take place in the nutrition of the 

 plant, in its absorptions and transpirations, in the amount of 

 heat, light, air and moisture, which it then habitually receives ; 

 finally, in the superiority which certain of the various vital 

 movements may acquire over others." 1 



Like his predecessors, and like those who followed him, 

 marck adduces in support of these views the remarkable 

 edifications which have taken place in animals and plants 

 under the influence of domestication : 



" That which nature does with the aid of much time, we do 

 every day by suddenly changing, in relation to some living plant, 

 the conditions under which it and all the individuals of its species, 

 have existed. 



" All botanists know that the plants which they transport from 

 their native place in order to cultivate them in gardens, undergo, 

 little by little, changes which, in the end, make them unrecogniz- 

 able. . . . 



"Is not the cultivated wheat (Triticum sativum) a plant 

 brought by man to the condition in which we now actually see 

 it? Who will tell me in what country such a plant occurs 

 naturally, that is to say except as the result of its cultivation in 

 some neighbouring place ? 



" Where do we find, in a state of nature, our cabbages, our 

 lettuces, &c., as we now possess them in our kitchen gardens ? 

 Is it not the same with respect to the many animals which 

 domestication has changed or considerably modified?" ' 



We may next consider two examples of the kind of evidence 

 which Lamarck brings forward in proof of the effects of the 



1 Op. oit., Tom. 1 pp. 22 1 223. 



2 Ibid., pp. 226-227. v 



