130 CARL R. MOORE 



sex condition are known not only for mammals in general, but 

 also for the human individual, but in every such case on record 

 there is an absence of function noted for one or for both sex 

 glands, at least so far as production of germ cells is concerned. 

 In a large majority of cases in which tissues or organs of both 

 sexes are present, either separate or in a mixed condition, the 

 animal is sterile; usually neither gland is capable of producing 

 the sex cells that it normally produces. 



Lillie's study of the free-martin^ has revealed a powerful influ- 

 ence of the internal secretions of the developing gonad on the 

 sexual apparatus of a developing foetus — so powerful, in fact, 

 that the whole trend of zygotic determination of sex may be 

 interfered with. And since the free-martin condition demon- 

 strates that secretions are produced by the sex glands long before 

 birth, we should be able to determine whether there is an antago- 

 nistic action between the secretions of the sex glands by trans- 

 planting gonads of the two opposite sexes into the same individual 

 shortly after birth, or by transplanting a gonad into an animal 

 of the opposite sex without castrating the latter. The success 

 of such transplantations is apparently much greater if performed 

 in the early life of the animal, and, furthermore, in the event 

 of an early transplantation more opportunity would be afforded 

 for an antagonism to assert itself; in the event of the existence 

 of such an antagonistic action, probably abnormal changes would 

 appear in the sex glands as growth and differentiation proceed, 

 and thus we would have definite experimental evidence bearing 

 upon the causes of hermaphroditism. 



In a reinvestigation of the possibilities of the gonads as modi- 

 fiers of somatic and psychical characteristics,^ the writer has 

 transplanted gonads in rats and guinea-pigs; the normal sex 

 gland was removed and a gland of the opposite sex substituted 

 for it. In such cases many, but not all, grafts obtained vascular 

 connections and persisted. During the series of operations some 

 cases of transplantation were carried out without previous 

 removal of the normal gonad; ovaries were transplanted into 



' Lillie, '17. 

 « Moore. '19 



