i.j VARIATION AND HEREDITY 79 



character is inconceivable. But if, perchance, experiment 

 should show that acquired characters are transmissible, 

 it would prove thereby that the germ-plasm is not so 

 independent of the somatic envelope as has been contended, 

 and the transmissibility of acquired characters would 

 become ipso facto conceivable; which amounts to saying 

 that conceivability and inconceivability have nothing 

 to do with the case, and that experience alone must settle 

 the matter. But it is just here that the difficulty begins. 

 The acquired characters we are speaking of are generally 

 habits or the effects of habit, and at the root of most habits 

 there is a natural disposition. So that one can always 

 ask whether it is really the habit acquired by the soma of 

 the individual that is transmitted, or whether it is not 

 rather a natural aptitude, which existed prior to the habit. 

 This aptitude would have remained inherent in the germ- 

 plasm which the individual bears within him, as it was 

 in the individual himself and consequently in the germ 

 whence he sprang. Thus, for instance, there is no proof 

 that the mole has become blind because it has formed the 

 habit of living underground; it is perhaps because its 

 eyes were becoming atrophied that it condemned itself 

 to a life underground. 1 If this is the case, the tendency to 

 lose the power of vision has been transmitted from germ 

 to germ without anything being acquired or lost by the 

 soma of the mole itself. From the fact that the son of a 

 fencing-master has become a good fencer much more quickly 

 than his father, we cannot infer that the habit of the parent 

 has been transmitted to the child; for certain natural 

 dispositions in course of growth may have passed from the 

 plasma engendering the father to the plasma engendering 



1 CuSnot, "La Nouvelle Th&me transformiste" (Revue generate des 

 sciences, 1894). Cf. Morgan, Evolution and Adaptation, London, 1903, 

 p. 357. 



