THE SPECIES 249 



The assumption of one pair of ancestors meets with such s/ 

 difficulties that, even in the case of races, it comes up against 

 contradictions. For even in the race the treasure-store of 

 genes is much too large to be united in one single pair. How 

 much the less can a single pair of parents contain all the genes 

 of all the species belonging to one genus ! 



But this very real difficulty, obvious though it must be 

 to everyone, was cheerfully ignored by the Darwinians, in a 

 manner ill-befitting the seriousness of the problem. 



The species as a means to classification 



As soon as we regard the species merely as a means to 

 classification, we take up a totally different position. In 

 such a case, we are no longer concerned with bringing into line 

 the whole wealth of species, but merely seek for a group of 

 characteristics that are displayed by all the individuals of 

 one species, and at the same time are typical of this species 

 alone. 



This is made possible by the fact that all the inter- 

 changeable properties of the individual organisms within 

 one species are built up on a stable basis of properties common 

 to them all. The species belonging to one genus have, in 

 addition, a smaller stock of properties, which, after removal 

 of the group of characters typical of each separate species, 

 remains over for the genus. 



If we continue on these lines, proceeding to larger and 

 larger animal groups, we gradually demolish the stock of 

 properties, until we come down to the first germinal rudiments 

 that determine the radiate or the bilateral type. 



When we start from the species, and ascend to the genus 

 and type as natural phenomena, the number of forms and 

 of properties increases with the size of the circle enclosing the 

 individuals ; but when we consider the species, genus and 



