126 CARL R. MOORE. 



spermatozoa in its seminiferous tubules within sixty days after 

 birth. By these operations we have prevented this and held 

 the testis in an undifferentiated condition for a period longer 

 than four months, yet have had recovery of function on scrotal 

 replacement; the implications from testes confined longer in the 

 abdomen are that similar results could have been obtained from 

 testes confined in the abdomen for over a year. Since three 

 years may fairly well represent the average duration of sexual 

 function in the guinea pig, one who is interested may carry the 

 implications to relative periods of retention in the human 

 individual and perhaps gain some insight to possibilities existing 

 in such conditions. From the fact that recovery in the guinea 

 pig may follow many months after the onset of sexual maturity, 

 we might expect that in the human individual of twenty-five to 

 thirty years, and from implications one considerably older, a 

 scrotal replacement might result in the production of a normal 

 testicle. It is obvious that these implications, though basically 

 sound, require exact study before they can be more than impli- 

 cations. From the nature of the case it is obvious that since 

 relatively few operations of this character are now attempted 

 on the human individual, and since it is not frequent that such 

 a replaced testicle will come to histological study, there is but 

 little exact data in the literature of any significance in making 

 such comparisons. Bevan ('18), among other surgeons, has 

 given considerable study to the problems on the human indi- 

 vidual, but it is well recognized that with one normal testis 

 besides a scrotally replaced one, about the only criterion of 

 effectiveness in its replacement would have to come from size 

 and firmness determined by palpation or perhaps from hypo- 

 dermic syringe samples. 



The nature of the influence on a prepubertal abdominally 

 retained testis by the opposite normal testis is not clear; the 

 spermatogenetic activity, however, does exert some influence on 

 the character of the undescended testis. Lipschutz ('25) has 

 recently shown that the expression of the ovarian influence in a 

 male animal by an ovarian transplant is likewise conditioned by 

 spermatogenetic activity; a normal testis prevents the expression 

 of the hormone influences of a transplanted ovary whereas a 



