422 V. THE NATURE OF EVOLUTION 



elasticity is revealed most strikingly in the genes. As previously men- 

 tioned, there are actually many other evidences that protein molecules 

 are elastic in themselves. The organisms having genes provided with 

 only weak rigidity or feeble elasticity must be very sensitive to en- 

 vironmental changes, by which will be induced profound and extensive 

 alteration in their characters. Therefore, if the rigidity in the structure 

 of the genes is reduced by some or other causes, the organisms will 

 commence an orthogenetic changes advancing rapidly with the extensive 

 specialization until they become extinct due to the overspecialization. 

 The progress of phage inactivation by formalin does not decline 

 as stated above, showing the relative weakness of the reversibility, but 

 in a weakly acid solution the diminution of the velocity is manifest, 

 and the progress frequently oscillates. Thus it can be said that phage 

 as a gene-model had a strong reversibility in a weakly acid solution, 

 but that in a neutral or an alkaline solution the reversibility is 

 lessened and accordingly formalin will cause an rapidly-advancing 

 orthogenetic change leading to the extinction of the phage. 



2. The Orthogenesis of Mankind 



As we have already seen, environmental factors including climate 

 appear to exert the influence mainly through the endocrine glands 

 especially hypophysis. Shapiro's work (92) on Japanese immigrants 

 to Hawaii has led to the same conclusion as that of Boas on migrants 

 from various Eeuropean countries to New York City. The Japanese 

 migrants are taller than their stay-at-home relatives, and the children 

 of the migrants depart further than do their parents. The children 

 of Japanese in Los Angeles are also known to be taller than their 

 kindred in Japan, the increase in size being especially distinct in legs 

 and arms as compared to that in the trunk. Such an increase in 

 stature may be readily explained by the assumption that the climate 

 or other environmental factors in Los Angeles and Hawaii stimulate 

 the function of hypophysis as will be detailed below. A similar 

 change is reported to occur also in New York in the immigrants of 

 Central European people, such as Bohemians. Slovaks, Hungarians, 

 Poles, and Hebrews, suggesting the presence of the same environmental 

 factor or factors also in New York. 



It has long been known that pathological hyperfunctions of 

 hypophysis result, on the one hand, in the gigantism in man, while, 

 on the other hand, the experimental gigantism in rat.s or dogs was 

 actually demonstated by injection of an extract of hypophysis. The 

 final proof for the existence of the growth hormone comes from the 



I 



