Different Kinds of Selection 133 



culties of diverse dimensions, and they answer back ; 

 the clash of the individual's new reactions against 

 environing limitations is the struggle for existence. 

 But in many cases there is an abundant crop of varia- 

 tions — good, bad, and indifferent — variations that 

 can be entailed on the offspring. Those organisms 

 that exhibit an advantageous variation will have an 

 advantage; those that have not this character, or 

 have some other that is disadvantageous, will be 

 handicapped. Provided the novel character has some 

 survival value, it is bound to prevail. Professor Pun- 

 nett has made the interesting calculation : "If a popu- 

 lation contains .001 per cent, of a new variety, and 

 if that variety has even a 5 per cent, selection ad- 

 vantage over the original form, the latter will almost 

 completely disappear in less than a hundred genera- 

 tions." Sometimes the sifting will be quick and sure : 

 "Off with his head, and there's an end of it"; but 

 sometimes it must be slow and subtle: A slightly 

 shorter adult life, a somewhat smaller family, a little 

 less success in launching them. In the course of time, 

 however, the results of the quick and the slow sifting 

 will be the same : the survivors will survive. They will 

 survive — this is the whole point — in virtue of the 

 possession of some advantageous character, includ- 

 ing fertility; or because they are free from some 

 weakness which is a fatal handicap to their fellows. 

 If it is one's ambition to possess a very fine lawn, 

 like that of some of the Oxford Colleges, one may 

 proceed by laboriously weeding year after year — 

 eliminating the plants, including perhaps coarse 



