HYBRIDS. , 367 



are hybrids, will not breed as a race, though they 

 generally can with either of the parent stocks, and 

 the result is a partial return to that stock ; and if 

 the system were continued, the ultimate progeny 

 would be again assimilated or identified with the 

 pure blood. 



Thus we can, with very little reflection, get 

 hold of the general principles that are to guide us 

 in our observation of animated nature. There is 

 a specific form handed down from race to race ; 

 and the general characters of that form cannot 

 be altered so that one species shall resemble or 

 merge into another. This character is in the 

 embryo, even when that is too minute for being 

 in any way the subject of observation. That 

 keeps them all true to their kinds in the general 

 way, so that we never find a cat taking to the 

 water and fishing at the bottom, as an otter 

 does, or a fish coming on land to hunt for worms. 

 As little do we ever find a hawk robbing orchards, 

 or a pigeon killing sparrows for food to its young. 



But it is the general character only which de- 

 scends by hereditary succession. When the young 

 leaves the parent, and becomes an independent 

 being, it is controlled by circumstances, and 

 must accommodate itself to them. Thus, in pro- 

 portion as the treatment varies, the individual 

 character must vary ; and that is the reason why 

 cultivated plants and animals are so much more 

 varied, in all their species, than wild ones. The 

 wild ones have only the changes of the seasons to 

 contend with, and as these are upon the average, 

 pretty nearly the same at the same place, there is, 

 in the same place and at the same time, very little 

 difference between any two wild animals of the 

 same species, if they are both of the same age. 



