HEREDITARY TRANSMISSION AND VARIATION. 89 



This tendency to variation is less marked in that 

 mode of propagation which takes place asexually; 

 it is in that mode that the minor characters of 

 animal and vegetable structures are most completely 

 preserved. Still, it will happen sometimes, that the 

 gardener, when he has planted a cutting of some 

 favourite plant, will find, contrary to his expectation, 

 that the slip grows up a little different from the 

 primitive stock — that it produces flowers of a differ- 

 ent colour or make, or some deviation in one wav or 

 another. This is what is called the ' sporting ' of plants. 



In animals the phenomena of asexual propagation 

 are so obscure, that at present we cannot be said to 

 know much about them ; but if we turn to that mode 

 of perpetuation which results from the sexual process, 

 then we find variation a perfectly constant occurrence, 

 to a certain extent ; and, indeed, I think that a certain 

 amount of variation from the primitive stock is the 

 necessary result of the method of sexual propagation 

 itself j for, inasmuch as the thing propagated proceeds 

 from two organisms of different sexes and different 

 makes and temperaments, and as the offspring is to 

 be either of one sex or the other, it is quite clear that 

 it cannot be an exact diagonal of the two, or it would 

 be of no sex at all ; it cannot be an exact intermediate 

 form between that of each of its parents — it must 

 deviate to one side or the other. You do not find 

 that the male follows the precise type of the male 

 parent, nor does the female always inherit the precise 

 characteristics of the mother, — there is always a pro- 

 portion of the female character in the male offspring, 



