TRANSFORMISM 253 



having antecedents or " causes." Perhaps the occurrence of 

 real " uncaused " novehies in the racial histories of organisms 

 may simply have to be accepted. 



86. ON HYPOTHESES OF TRANSFORMISM : 

 I. NATURAL SELECTION 



We have not considered those variations that we have called 

 " acquirements " because it will be more convenient to deal with 

 them when we discuss " Neo-Lamarckism." Meanwhile it has 

 to be emphasized that the occurrence of novelties of character is 

 the starting-point in any hypothesis of transformism that involves 

 selection. The occurrence of a novelty, or a mutation (as we 

 may agree to say), is not, in itself a transformist process, for the 

 latter must include the establishment of an enduring category 

 of organisms. A mutation is a change which may occur in one, 

 or in a few individuals of a population, but some process must 

 go on w^hereby the novelty of character becomes widespread in 

 the population so that a new '* breed," " race " or species comes 

 into existence. Further, the new category must, in some way, 

 become physiologically isolated from other ones originally 

 associated with it so that it will tend, at all events, not to interbreed 

 with those other categories. 



S6a. The Modes of Origins of Races of Domesticated 

 Plants and Animals are not necessarily those of New 

 Categories of Wild Organisms. This we can see when we 

 consider how such domesticated races originate and are main- 

 tained. Breeders, farmers and agriculturists observe the occur- 

 rence of some noticeable " sport " or mutation, or they observe 

 that some individual organisms, rather than others, have 

 desirable qualities : fruits may be larger or more succulent ; the 

 grains of some cereals may make better bread-stuffs ; milch 

 cows may give a better yield, etc., or the sport may be desirable 

 merely by its appearance (as in fancy pigeons, some dogs, some 

 cats, etc.). In any case there is the motive of perpetuating the 

 novelty in a race, or breed, and so the organisms that display it 

 are inbred, or are self-fertilized, or reproduced asexually if they 

 are plants. That is to say, the breeder exercises control over 

 the reproduction of the individuals that he wishes to perpetuate 

 by selecting, for interbreeding, those that have the desired 



