112 Dynamic Theory. 



the Chinese taking advantage by selection of these freaks have man- 

 aged to develop a number of special races, among which are some hav- 

 ing an extra number of tails. 2 These facts illustrate well the possibility 

 of life inhering in anomalous and unusual forms. Yet these forms 

 would not in a state of usual conditions be able to maintain themselves 

 and perpetuate their peculiarities in a posterity. If left to themselves 

 "they sooner or later succumb in the struggle for existence." But 

 when proper conditions are artificially supplied almost any sort of mon- 

 strosity is able to propagate itself. In an ordinary state of nature it is 

 obvious that one generation cannot be allowed to vary greatly from its 

 predecessor, because its environment is so similar to that of its prede- 

 cessor that any freaks or departures from the ancestral type, if too great, 

 become a burden instead of a help, and the individuals who happen to 

 labor under such burden fail in the struggle for existence and so do not 

 perpetuate their peculiarities. 



But on the other hand, it is obvious that any peculiarity or variation 

 from the ancestral type that is advantageous to its possessor, and better 

 fits it for making its way against competition, will make it stronger also 

 to perpetuate such peculiarity in its posterity. Because use confirms 

 and crystallizes habit, and it is habit or constant functional activity 

 that first modifies and finally fixes and consolidates a peculiarity of 

 form ; and when any peculiarity of form becomes fixed it becomes regu- 

 larly and normally transmissable, and from being an individual mon- 

 strosity becomes at length a specific or race peculiarity. But most of 

 the variations from a family or race type that occur in individuals are 

 of an extremely slight description and from the uniformity and wide ex- 

 tent of similar causes are apt to be alike in many individuals at the 

 same time ; and from the persistence of the causes the variations are apt 

 to be continuously supplemented by additions in the same direction, 

 making the tendency not only to confirm the variations but to increase 

 them. 



As an example, suppose a certain island to be inhabited by a race of 

 rabbits that browse upon the herbage, and a pack of wolves whose only 

 resource for a livelihood consists of the rabbits which they hunt. The 

 process of hunting calls into play certain activities a keen sense of 

 sight to quickly spy the prey, and quick senses of hearing and smell to 

 detect the prey when not in sight ; speed of limb to enable the hunter to 

 catch the prey, and sagacity to cause the hunter to place himself be- 

 tween the prey and his burrow or safe retreat, or to place himself on the 

 leeward side of his intended victim, or to reduce his distance from him 

 by silently creeping up under cover. No individual can exercise these 

 several faculties without strengthening them, any more than he can suf- 



2 Harper's Annual, 1874, 294. 



