INTENSIVE SEGKEGATION. 317 



TransformatoLU snould be considered a separate principle, for it 

 seems to be simply the inberitauce by offspring of characters that 

 have for many generations been united in the endowments of at 

 least a portion of their ancestry, and the correlation of these 

 endowments must have been produced through the action of 

 other principles. 



The prevalence of males in times of pressure, with the prevalence 

 of females in times of plenty, is regarded by Dr. W. K. Brooks, 

 of Johns Hopkins University, as a characteristic established 

 by natural selection, by which the organism acquires variability 

 or fixity of type according as either character is most needed ; for 

 according to his observations the males represent the former, and 

 the females the latter element. There can be no doubt that in 

 many species the males are more variable than the females, and 

 that in some of the same species the proportion of males increases 

 with the degree of adversity ; but this does not seem to be suffi- 

 cient ground for maintaining that the increase in the proportion 

 of males will increase the variability of the offspring. Increase 

 in the number or amount of the variable element does not neces- 

 sarily involve increase in the variability of either element, or 

 in the offspring of both. I find need of additional factors in order 

 to bring these facts into any relation to the increase of variability. 

 Granting that the sperm-cell is the source of variation and the 

 germ-cell the source of fixity, and that increased tendency to 

 variation in the offspring will be secured by an increased range 

 of variation in the sperm-cells, it does not follow tbat increase in 

 the relative number of males will increase the range of variation 

 in the sperm-cells, and therefore in the offspring. But if conflict 

 with the environment and the winnowing process of natural 

 selection falls most heavily upon the males, there must be some 

 advantage in having their relative numbers increased in times of 

 adversity ; and if the exposure of parents to hardships increases 

 the variability of either male or female offspring, and especially 

 if it increases the variability of both, plasticity will be increased. 



Prof. Cope's "Doctrine of the Unspecialized " (' Origin of the 

 Fittest,' pp. 232-5) rests on the fact that the most highly special- 

 ized types, as well as individuals, are most likely to be exterminated 

 by extraordinary changes in the environment; and Mr. Hyatt's 

 " Geratology " (' Proceedings of the American Association,' vol. 

 xxxii. pp. 349, 360) teaches that types that are being slowly ex- 

 terminated usually assume forms resembling those produced by 



