VII. NON-ISOLABLE RACES. 



§ 22. TRIFOLIUM INCARNATUM QUADRIFOLIUM. 



Few experiences are so well fitted for enabling us to 

 obtain an insight into the nature of specific characters as 

 the failure of an experiment in selection. I am not speak- 

 ing of practical experiments because in such cases the 

 breeder is often disappointed by the fact that the result 

 is not superior to what he has already, or is not suitable 

 for cultivation on a large scale from other causes. This 

 kind of failure only concerns the practical breeder and 

 does not affect the scientific investigator. The object of 

 the latter is simply to find out whether a race specified 

 beforehand can be obtained or not. 



According to the theory of selection almost anything 

 ought to be obtainable. Almost all characters manifest 

 fluctuating variability to the extent requisite for selection. 

 If the range of variation is considerable, selection should 

 proceed rapidly; if it is within narrower limits it should 

 merely require longer series of generations; and if, more- 

 over, the familiar but undemonstrated opinion is assumed 

 that fluctuating variability increases as the result of the 

 selectixe ])rocess, there is no reason why in any given 

 case the attempt to breed a desired race should not suc- 

 ceed. 



But this discussion, in my opinion, onlv applies to 

 ordinary fluctuating variability, and if thus limited, I 



