990 E\OLUTIONAL MODIFICATIONS 



especially in fetal and infantile life, the pineal body has much the appearance 

 of a glandular structure. There seems fair probability that it is actually a 

 gland which contributes its secretion directly to the blood in these periods of 

 life. It has been maintained that its function is to check the development, 

 not only of the rigid skeleton, but also of sexual differentiation and maturity. 

 If destroyed b}' disease, these inhibitory qualities arc lost and precocious 

 development of body stature with premature differentiation of sexual 

 activities result. This, in fact, is the clinical syndrome, well recognized for 

 nearly a quarter of a century and kno\\n as macrogenitosomia praecox. 



These and many similar facts would indicate a functional activity on the 

 part of the pineal gland. Whatever claims may be urged for it in regard to the 

 specialized inhibitors* function, which it exerts upon the maturation process in 

 development, should not be accepted without much reservation. There is great 

 room for improving our understanding both of the structure and the functional 

 activity of this portion of the nervous system. It is of interest, however, 

 that the size of the pineal fossa progressively increases from the lowest of 

 the primates to man. This indicates, no doubt, that the pineal gland itself 

 correspondingly increases in size, and thus adds to the process of growth a 

 decisive inhibitory factor which holds in abeyance the development of 

 maturity in the human race. It is noteworthy in this connection to recall the 

 pertinent note made by Alfred Russell W ullaee concerning the baby orang- 

 outang which he once captured and observed. In his efforts to ameliorate 

 the discomforts of infancy, which this orphaned orang suffered, he placed 

 with it, as companion, a young macaeus monkey of about equal age. The 

 great disparity in their reactions was apparent at once. The lower primate, 

 although an infant, showed almost all of the activities of the adult. It was 

 constantly in search of food on its own initiati\e and not in any way 

 embarasscd by the fact that it had been deprived of maternal care. The young 

 orang, on the other hand, lay continually upon its back as might a human 



