THE GROWTH OF GROUPS 27 



by a process of diminution ending in unity and zero, so 

 its growth is brought about by numerical increase from 

 unity. 



The term group is used here in preference to the term 

 species, since, although it is no less conventional, it is 

 far more definite. It cannot be made to vary as can the 

 term species. In any discussion on the origin of species 

 one is always brought face to face with difficulties arising 

 from the varying meaning of the term species. In such 

 discussions one must point to a certain so-called species 

 X and attempt to demonstrate the history of its origin, 

 but even if one succeeds in the demonstration, one's 

 opponent may say, " After all, X is not a fair example of 

 a species." 



The term group, as used here, is not synonymous with 

 the usual term species, although it seems evident that a 

 large proportion of our denned species are groups, in this 

 sense. 



AN OBJECTION 



The chief objection to these propositions is the sup- 

 posed evil effect of inbreeding. They will appear absurd 

 to any one who is convinced that a pair of animals or a 

 single plant cannot give rise to a million or more de- 

 scendants, because such an occurrence would be contrary 

 to the laws of nature. What is the evidence for the ill 

 effect of inbreeding ? Most practical breeders are of the 

 opinion that inbreeding is bad, but a few have considered 

 that it is apparently harmless and the only method of 

 raising pure stock. In considering the question we must 

 remember that prejudice may influence our opinion, 

 since for many centuries incest has been naturally 



