LECTURE VI 



STABILITY AND REAL ATAVISM 



It is generally believed that varieties are 

 principally distinguished from species by their 

 inconstancy. This conception is derived from 

 some special cases and transferred to others, 

 and in its common form this belief must have 

 originated from the confusion which exists as 

 to the meaning of the term variety. It is 

 true that vegetative varieties as a rule run back, 

 when propagated by seeds ; they are an obvious 

 instance of inconstancy. In the second place 

 we have considered the group of inconstant or 

 sporting varieties, which of course we must ex- 

 clude when studying the stability of other types. 

 However, even these sporting varieties are un- 

 stable only to a certain degree, and in a broader 

 sense will prove to be as true to their character 

 as the most constant types. 



Having separated these two groups, which 

 include also the wide range of hybrid forms, we 

 may next consider only those varieties of pure 

 origin, and ordinarily propagated by seeds, 



154 



