416 V. THE NATURE OF EVOLUTION 



■due to the disfunction of adrenal cortex. As we have seen above, 

 climatic factors exert influences upon hypophysis, which in turn governs 

 adrenal cortex. We beleive still at present that our conclusion was 

 reasonable. 



The lack of stimulating climatic factors proposed by Huntington 

 may induce a disturbance of the pituitary function followed by a change 

 in the feature of hormonal secretion, especially by a disorder of adrenal 

 cortex resulting in the change of human characters. The continued 

 lack of the factors for successive generations may lead to the fixation 

 of the characters peculiar to the climate. The increase in the strength 

 ■of the factors may, on the other hand, change the characters in the 

 opposite direction. 



There has long been a strong conviction among anthropologists 

 that head form is the most reliable element in the classification of 

 race, but Boas (86) in measuring with many immigrants and their 

 •children in New York City proved that even the cephalic indexes 

 ^vhich were formerly considered permanent racial traits are changeable 

 by environment. Thus, the children of broad-headed Jew from Poland, 

 iDorn in New York, proved to be less broad-headed than the parents. 

 Moreover, the reduction in breadth of head of the children increased 

 in accordance with the duration of the residence of the mothers in New 

 York. Another group of im.migrants consisted of long-headed people 

 from southern Italy. In their cases, also, there was a slight but 

 significant difference between the American-born children and their 

 parents or brothers and sisters born in Europe. This difference, too, 

 increased as the time elapsed since the immigration of the parents. 

 In this case, however, the change was towards greater instead of less 

 breadth of head. In other words, each type of children tended somewhat 

 away from the standard physique of the parent, and towards a less 

 extreme middle type. 



This middle type might be, therefore, the standard physique in 

 New York, determined by the environmental factors, probably chiefly 

 those of climate, prevailing there. It should be noted that the change 

 in the children was increased with the duration of residence of the 

 mothers. This fact indicates that the influence of the prolonged resi- 

 dence exerted on the mother was transmitted to the children, proving 

 ■clearly the inheritance of the acquired character. 



2. The Inheritance of Habitude 



The environmental effects which change the human characters may 

 not be involved in climate only as will be considered later, but the fate 



