PHYSIOLOGY, CHEMISTRY AND PATHOLOGY 



11 



ditions for the two groups were identical. At the end of ten weeks the 

 pineal fed group had gained 23 per cent in excess of the control group. 



This excess in weight of pineal fed guinea pigs over their controls was 

 a symmetrical overgrowth. There was some increased adipose tissue, but 

 this was generally distributed and not localized in any one region of the 

 body. At no time was it possible to continue this excessive growth above 

 normal adult size. As the animals approached adult size the pineal feed- 

 ing became less effective, and after full maturity was attained, was without 

 further effect. There was no tendency to gigantism. 



Investigation of Precocious Sexual Development from Pineal Feeding. 

 In view of the supposed relationship between the pineal body and puber- 



Fig. 1. Effects on the growth of young guinea pigs of feeding with small quan- 

 tities of pineal glands. Larger, sleeker animals on right, pineal fed; animals on 

 left, controls. Average animals from a series of 50. Pineal fed animals were 23 per 

 cent larger than controls in ten weeks. (From McCord, J. Amer. M. Ass., Chicago.) 



tas precox, experiments were carried out to determine whether any relation 

 might be demonstrated between pineal feeding and precocious sexual 

 development. A group of forty-eight guinea pigs was divided into test 

 and control lots. There was an equal number of males and females in 

 each lot, but the males and females were separated. The test pigs -were 

 fed calves' pineal tissue in 10 mg. amounts daily. Feeding was begun 

 when the animals were two weeks old and continued for nine weeks. The 

 males and females of each group were then placed together in breeding 

 pens. As a measure of any difference in sexual development it was 

 thought desirable to note the date of birth of young in the two lots. All 

 except two of the pineal fed animals gave birth to young, before the first 

 of the controls. Fourteen days elapsed between the birth of the young of 

 the first pineal fed, and the first control animals. In all cases the young 

 were normal and in no wise different from any other young guinea pigs. 



