VARIATION UNDER DOMESTICATION. 11 



The results of the various, unknown, or but dimly under* 

 stood laws of variation are infinitely complex and diversified. 

 i*.t is well worth while carefully to study the several treatises 

 on some of our old cultivated plants, as on the hyacinth, 

 potato, even the dahlia, etc. ; and it is really surprising to 

 note the endless points of structure and constitution in 

 which the varieties and sub-varieties differ slightly from 

 each other. The whole organization seems to have become 

 plastic, and departs in a slight degree from that of the 

 parental type. 



Any variation which is not inherited is unimportant for 

 us. But the number and diversity of inheritable deviations 

 of structure, both those of slight and those of considerable 

 physiological importance, are endless. Dr. Prosper Lucas' 

 treatise, in two large volumes, is the fullest and the best on 

 this subject. No breeder doubts how strong is the tendency 

 to inheritance ; that like produces like, is his fundamental 

 belief ; doubts have been thrown on this principle only by 

 theoretical writers. When any deviation of structure often 

 appears, and we see it in the father and child, we cannot 

 tell whether it may not be due to the same cause having 

 acted on both; but when among individuals, apparently 

 exposed to the same conditions, any very rare deviation, due 

 to some extraordinary combination of circumstances, appears 

 in the parent — say, once among several million individu- 

 als — and it reappears in the child, the mere doctrine of 

 chances almost compels us to attribute its reappearance to 

 inheritance. Every one must have heard of cases of al- 

 binism, prickly skin, hairy bodies, etc.. appearing in several 

 members of the same family. If strange and rare deviations 

 of structure are really inherited, less strange and commoner 

 deviations may be freely admitted to be inheritable. Per- 

 haps the correct way of viewing the whole subject would 

 be, to look at the inheritance of every character whatever 

 as the rule, and non-inheritance as the anomaly. 



The laws governing inheritance are for the most part 

 unknown. No one can say why the same peculiarity in 

 different individuals of the same species, or in different 

 species, is sometimes inherited and sometimes not so; why 

 the child often reverts in certain characteristics to its grand- 

 father or grandmother or more remote ancestor; why a 

 peculiarity is often transmitted from one sex to both sexes, 

 or to one sex alone, more commonly but not exclusively to 

 the like sex. It is a fact of some importance to us, that 



