388 COOK 



tions are at once degenerative and reconstructive, just as the high 

 temperature which attends many diseases of the human organ- 

 ism is at once an evidence of illness and an indication of con- 

 structive systemic reaction. Indiscriminate crossing of muta- 

 tive varieties tends to restore the wild type of the species. 

 Mongrel dogs are wolfish ; mongrel pigeons, even of white 

 ancestry, are blue ; mongrel roosters become red in approxi- 

 mating the primitive game breeds ; mongrel flowers are single 

 and small. 



Stronger evidence could scarcely be demanded for proving 

 that the interbreeding of the members of a species is a measure 

 of organic stability, not a stationary or uniform stability, but a 

 stability of coherent symbasic motion. 



EXAGGERATED HETERISM OF CLONIC HYBRIDS. 



Further evidence that mutations are reactions from abnormally 

 restricted descent may be drawn from the results of sexual re- 

 production among clonic varieties. The sexual offspring of 

 plants which have been subjected to considerable periods of 

 vegetative propagation always show a very large amount of in- 

 dividual diversity. This has caused them to be reckoned as 

 hybrids, though in reality they represent a very distinct type 

 of evolutionary phenomena. Each clonic variety is, after all, 

 only an individual member of its species, and as such varieties 

 have not been selected or bred to uniformity, in the sense of 

 coming true to seed, they and their offspring might be expected 

 to retain the original amount of heterism or normal individual 

 diversity of the wild type of the species. As a matter of fact 

 the sexual offspring of clones have an individual diversity of 

 the order of mutations. The only difference appears to be that 

 all the individuals may be mutants, instead of the relatively 

 small percentages usually appearing in species which have been 

 subjected to courses of selective inbreeding for the elimination of 

 heterism. 



DIVERSITY RELATIONS BETWEEN SUBSPECIES WITH 

 RESTRICTED DESCENT. 



As long as the diversity of the members of species appears 

 either as the merely accidental or arbitrary result of environ- 



