in.] ORGANIC STABILITY. 31 



electrical batteries was that which is still known as a 

 Grove battery, being the invention of Sir William Grove. 

 Its principle was quite new at the time, and it continues 

 in use without alteration, 



The persistence in inheritance of trifling characteristics, 

 such as a mole, a white tuft of hair, or multiple fingers, 

 has often been remarked. The reason of it is, I presume, 

 that such characteristics have inconsiderable influence 

 upon the general organic stability ; they are mere 

 excrescences, that may be associated with very different 

 types, and are therefore inheritable without let or 

 hindrance. 



It seems to me that stability of type, about which we 

 as yet know very little, must be an important factor in 

 the general theory of heredity, when the theory is 

 applied to cases of high breeding. It will be shown 

 later on, at what point a separate allowance requires 

 to be made for it. But in the earlier and principal 

 part of the inquiry, which deals with the inheritance of 

 qualities that are only exceptional in a small degree, a 

 separate allowance does not appear to be required. 



Infertility of Mixed Types. — It is not difficult to see 

 in a general way why very different types should refuse 

 to coalesce, and it is scarcely possible to explain the 

 reason why, more clearly than by an illustration. Thus 

 a useful blend between a four-wheeler and a hansom 

 would be impossible ; it would have to run on three 

 wheels and the half-way position for the driver would 

 be upon its roof. A blend would be equally impossible 



