SCROTAL REPLACEMENT OF CRYPTORCHID TESTES. 12 7 



cryptorchid testis does not prevent it. The effect of the influence 

 on a unilaterial abdominal testis is expressed by an almost entire 

 suppression of any developmental capacities. In contrast to 

 this the cryptorchid testis uninfluenced by spermatogenesis in 

 another testis undergoes decided modification. In earlier reports 

 (Moore, '240) it was noted that replacement of abdominal testes 

 that had undergone this change was not followed by normal 

 gametogenetic function. It is believed that the degeneration of 

 such testes had proceeded to the extent that all germinal cells 

 were removed from the tubules. 



The radical difference between the four or five month crypt- 

 orchid testis here described and the condition following within 

 90 days after replacement in the scrotum, serves as a striking 

 demonstration of the difference between the capabilities of a 

 given testis retained in the abdomen and one replaced in the 

 scrotum. Having remained embryonic in character and rela- 

 tively quiescent for months, it rapidly becomes engaged on a 

 constructive program and fulfills the primary function of the 

 organ before the end of three months. Thus the scrotal influence 

 is necessary for the expression of the potentialities of the organ 

 and the reader is referred to previous articles for the many lines 

 of evidence that have led to the conception that the effective 

 principle involved is a heat regulatory function on the part of 



the scrotum. 



SUMMARY AND CONCLUSION. 



1 . Guinea pig testes elevated from the scrotum to the abdomen 

 shortly after birth (prespermatogenic) will, if opposed by a 

 normal testis, retain an undifferentiated character practically 

 throughout the life of the animal. If unaccompanied by a 

 normal testis, they undergo changes leading to the enlargement 

 of seminiferous tubules lined with cells of Sertoli, relative increase 

 of interstitial cells, and a general condition unlike that of the 

 embryonic type. 



2. Replacement in the scrotum of the testis retained in the 

 abdomen for five months was followed by normal activity and 

 differentiation of spermatozoa in eight out of nine cases. Pre- 

 sumably normal development of abdominal testes confined in 

 the abdomen for much longer periods would follow scrotal 

 replacement. 



