276 SCIENCE AND PHILOSOPHY OF THE ORGANISM^ 



The name of " acquired characters ' : may a priori be 

 given to three different types of phenomena : firstly, varia- 

 tions including mutations ; secondly, disease or injuries ;, 

 and thirdly, the results of the actual process of adaptation 

 of every kind. 



In the first of these groups, the true problem of the 

 inheritance of " acquired " characters appears only with 

 certain restrictions. All variations and mutations are indeed 

 " acquired 3; by one generation so far as the earlier genera- 

 tion did not possess them, but mutations, at least, cannot 

 be said to be acquired by the actual adult personality : 

 they are innate in it from its very beginning, and therefore 

 may better be called congenital. 1 Congenital properties of 

 the mutation type are, in fact, known to be inherited : their 

 inheritance does not present any problem of its own, but is 

 included in the changes of the hereditary condition to 

 which they are due altogether. 2 All properties of the 

 variation type, on the other hand, having been studied 

 statistically, are known to be inherited, to a certain small 

 extent, as we have seen already whilst studying Darwinism, 

 though they are possibly always liable to reversion. 

 Modern science, as we know, 3 regards them as due to 

 changes of nutrition, in the most general meaning of the- 

 word. Under such a view variations might indeed be said 



1 This would not be true, if the varieties of plants produced by Blariug- 

 hem, Klebs, and MacDougal by means of external agents were really 

 "mutations" (comp. page 238, note 3). 



2 Of course, the inheritance of mutations would imply a certain sort of 

 " inheritance of acquired characters," on the condition stated in the pre- 

 ceding note. But, probably, the germs of the next generation might be 

 regarded here as being directly affected by the external agent, in a manner 

 that will briefly be mentioned later on in the text. 



3 Comp. page 238, note 2. 



