mTKODUCTION 25 



of some 700 per cent in the pancreas, hence such diabetes would indicate 

 a high degree of functional insufficiency. 



On the whole the evidence now available does not permit any very 

 definite conclusions as to what extent endocrin factors play a causal role 

 in senescence. That there is no inherent necessity of senile degeneration 

 has been claimed by various well informed biologists. The forestalling 

 of the degenerative changes would seem to depend upon the maintenance 

 of anabolic activity in the body cells. The endocrin organs admittedly 

 have an important influence on the fundamental metabolic processes. It 

 would seem, therefore, that further , study could profitably be devoted to a 

 determination of the extent to which endocrin changes normally precede 

 those in the body at large, and to what degree such changes may be pre- 

 vented or even reversed by judicious endocrin therapy. 



Endocrin Factors Determining Racial and Individual 



Characteristics 



The fact that certain of the racial characteristics by which anthropo- 

 logical types are set off are not dissimilar to those resulting from certain 

 ductless gland anomalies has not escaped the attention of speculative 

 endocrinologists. Keith, for instance, has written engagingly upon this 

 subject. In this connection we may consider especially variations in 

 stature, in bodily and facial configuration, in pigmentation, and in growth 

 and distribution of hair. 



That the races of mankind vary markedly in stature is well known. 

 The tall northern European is in striking contrast with the pigmy races, 

 such as are found in Africa and other tropical or subtropical regions. 

 The precise geographical distribution of such variants is a matter outside 

 the scope of this work. Experimental and clinical investigations have 

 shown that the hypophysis is capable of exercising a profound influence 

 upon the length of the body and the limbs of the individual subject, This 

 is well brought out in succeeding chapters on gigantism and dwarfism. 

 At this point suffice it to say that it has been possible to show that many 

 cases of gigantism have been characterized by enlargement of the hypoph- 

 ysis, as shown by skiagrams or measurements of the sella turcica, as well 

 as by direct post-mortem examination. That hyperfunctioning of the 

 hypophysis beginning before puberty leads to prolonged growth of the 

 long bones and the trunk is generally accepted. On the other hand, hypo- 

 physial deficiency is ordinarily .regarded as an important factor in 

 dwarfism. A relative preponderance of hypophysial function, then, if it 

 occurred as a racial characteristic, might well result in augmented average 

 height, just as depressed functioning might lead to pigmy types. 



Another possible factor in the regulation of height is the action of the 



