160 THE GROWTH OF GROUPS 



classification, using the term as opposed to conventional 

 classification. Take, for example, the mental disorder 

 known as Dementia prcecox, it is regarded by alienists as 

 a definite group, and it contains sub-groups, Hebephrenia, 

 Katatonia, and Dementia paranoides, and no doubt these 

 might be subdivided. The similarity between this 

 method of classification and that used by the naturalist 

 is evident, and this taken in conjunction with the fact 

 that these disorders are inheritable, makes it worth 

 while to examine the assumption that such disorders are 

 essentially similar to the inheritable variation of living 

 things in general. 



To regard a demented person as a mutant may not 

 appear useful at first sight. The name is not an explana- 

 tion, we know very little about mutants, we cannot 

 control their occurrence. But mutation is a process 

 concerning the whole tree of life and eventually we shall 

 know more about it and perhaps even control it to some 

 extent; hence it is worth while to consider the many 

 resemblances between abnormal mental subjects and 

 mutants. 



If they are mutants they are unsuccessful ones, unfit, 

 predestined to fail. In the living kingdom the unsuc- 

 cessful mutant is as evident as the successful one, though 

 less conspicuous. Some cannot reproduce their kind 

 at all, others can do so for a generation or two, they are 

 none the less mutants, i.e. distinct kinds thrown off 

 again and again from an established or successful kind. 



The Mutation Theory will probably be found useful 

 in psychiatry, the modern study of mental anomalies, at 

 any rate the possibility of its being so should be con- 

 sidered. 



