Variation of Individual Hereditary Characters 19 



neither according to sex nor to generation, nevertheless 

 they are distinguished by attributes which are as constant 

 and of the same order as the specific attributes taken from 

 the same organs in allied genera. 



In the way of a supplement I will consider, in this 

 connection, the alternation of generations, because here 

 also the differences between the physiologically non- 

 equivalent individuals, belonging to different generations, 

 are of the same order as the specific characters. This we 

 are taught by the Uridineae and the Cynipideae, and all 

 those cases where the presence of an alternation of gen- 

 erations was discovered only after the single forms had 

 been described as species, and had been classified with dif- 

 ferent genera and families of the system. And even to- 

 day it is impossible to prove morphologically that two 

 forms belong together; experimental cultures alone can 

 decide this question. The successive alternating genera- 

 tions cannot be reduced to the same primary form, for 

 each of them compounds its characters by means of a dif- 

 ferent selection from the available hereditary endow- 

 ments of the species. 



In summing up the result of this paragraph and the 

 two preceding ones, we find that every thorough consid- 

 eration of a specific character, and every comparison of 

 this with other characters, leads us to regard the former as 

 a mosaic, the component parts of which can be put to- 

 gether in various ways. 



4. The Variation of the Individual Hereditary Charac- 

 ters Independently of One Another 



A comparative consideration of the organic world 

 convinced us that the hereditary characters of a species, 

 even if connected with each other in various ways, are 



