456 GENERAL ItESULTS. Chap. XII. 



same species growing in a state of nature near together, 

 have not really been subjected during several previous 

 generations to quite the same conditions. 



Some naturalists assume that there is an innate 

 tendency in all beings to vary and to advance in 

 organisation, independently of external agencies ; and 

 they would, I presume, thus explain the slight 

 differences which distinguish all the individuals of the 

 same species both in external characters and in con- 

 stitution, as well as the greater differences in both 

 respects between nearly allied varieties. No two 

 individuals can be found quite alike ; thus if we sow a 

 number of seeds from the same capsule under as nearly 

 as possible the same conditions, they germinate at 

 different rates and grow more or less vigorously. They 

 resist cold and other unfavourable conditions differently. 

 They would in all probability, as we know to be the 

 case with animals of the same species, be somewhat 

 differently acted on by the same poison, or by the same 

 disease. They have different powers* of transmitting 

 their characters to their offspring ; and many analogous 

 facts could be given. Now, if it were true that 

 plants growing near together in a state of nature had 

 been subjected during many previous generations to 

 absolutely the same conditions, such differences as those 

 just specified would be quite inexplicable ; but they 

 are to a certain extent intelligible in accordance with 

 the views just advanced. 



As most of the plants on which I experimented 

 were grown in my garden or in pots under glass, a few 

 words must be added on the conditions to which they 

 were exposed, as well as on the effects of cultivation. 

 When a species is first brought under culture, it may 



r 



* YUmorin, as juoted by Verlot, 'Des Variety,' pp. 32, 38, 39. 



