DIFFICULTIES 15 



Before leaving this subject well to observe that 

 it was shown that a certain amount of variation is 

 consequent on mere act of reproduction, both by 

 buds and sexually, is vastly increased when parents 

 exposed for some generations to new conditions 1 , 

 and we now find that many animals when exposed 

 for first time to very new conditions, are (as) incapable 

 of breeding as hybrids. It [probably] bears also on 

 supposed fact of crossed animals when not infertile, 

 as in mongrels, tending to vary much, as likewise 

 seems to be the case, when true hybrids possess just 

 sufficient fertility to propagate with the parent 

 breeds and inter se for some generations. This 

 is Koelreuter's belief. These facts throw light on 

 each other and support the truth of each other, we 

 see throughout a connection between the reproduc- 

 tive faculties and exposure to changed conditions 

 of life whether by crossing or exposure of the indi- 

 viduals 2 . 



Difficulties on theory of selection 3 . It may be 

 objected such perfect organs as eye and ear, 

 could never be formed, in latter less difficulty 

 as gradations more perfect; at first appears mon- 

 strous and to (the) end appears difficulty. But think 

 of gradation, even now manifest, (Tibia and Fibula). 

 Everyone will allowif every fossil preserved, gradation 



have been intended to replace an earlier sentence. I have thought it best 

 to give both. In the Origin, Ed. i. p. 141, vi. p. 176, the author gives his 

 opinion that the power of resisting diverse conditions, seen in man and 

 his domestic animals, is an example " of a very common flexibility of con- 

 stitution." 



1 In the Origin, Ed. i. Chs. i. and v., the author does not admit repro- 

 duction, apart from environment, as being'a cause of variation. With regard 

 to the cumulative effect of new conditions there are many passages in the 

 Origin, Ed. i. e.g. pp. 7, 12, vi. pp. 8, 14. 



' J As already pointed out, this is the important principle investigated 

 in the author's Cross and Self -Fertilisation. Professor Bateson has 

 suggested to me that the experiments should be repeated with gametically 

 pure individuals. 



3 In the Origin a chapter is given up to " difficulties on theory " : the 

 discussion in the pi'esent essay seems slight even when it is remembered 

 how small a space is here available. For Tibia &c. see p. 48. 



