3O2 CARL RICHARD MOORE. 



the spayed female adrenal (.5616 gram), one sees that the normal 

 female adrenal is approximately 22.7 per cent, heavier than those 

 of the spayed female. Since the body-weight comparison shows 

 a difference of but I per cent., the conclusion is that spaying is 

 followed by an inhibition of the growth of the adrenal gland. 



Aside from the present data for the guinea pig there is appar- 

 ently but one other set of data that gives an adequate comparison 

 of the suprarenal weights in the two different sexes. Livingston's 

 data ('16), consisting as it does of suprarenal weights at different 

 ages and conditions of life, is inadequate for an intelligent com- 

 parison. Hatai ('15), however, found for the rat a marked sex- 

 ual difference in the weights of the suprarenal glands. The 

 female glands are approximately double those of the males in the 

 mature animals. For the guinea pig there is also a decided sexual 

 difference in the suprarenal weights, but in these animals it is the 

 male that is the larger. At the end of one year the male supra- 

 renals are approximately 20 per cent, greater in weight than those 

 of the female. 



Certainly to understand the general relationship existent be- 

 tween the suprarenals and the sex glands more data are desirable ; 

 particularly is this true for the guinea pig, in which the number 

 of animals is inferior to that of the rat. Obviously it is useless 

 to attempt an analysis of the conditions until the facts are well 

 established. 



One may well conclude that the same is true for the effects 

 derived after gonadectomy, and particularly so in view of the 

 many discrepancies noted in the literature. The fundamental 

 conditions of the various experiments are so varied that only 

 divergent results can be anticipated. Soli ('09) reports a decrease 

 in the relative weight of the suprarenals after castration in guinea 

 pigs, rabbits, and chicks, but the number of animals observed was 

 small. Marrassini and Luciani ('n) reported considerable data 

 on the suprarenal weights in both sexes of the rabbit and guinea 

 pig after gonadectomy, but in their experiments the time limit was 

 too brief for complete changes to have been registered. Castrated 

 and spayed males and females were compared with normal animals 

 of approximately the same age, but the operated animals were 

 killed in all cases within ninety days after the operation, and sev- 



