Thales Martins 391 



the scrotal pouch (pi. i, figs, i to 3); after cessation of treatment, they returned 

 to their intra-abdominal position. 



In the rhesus monkeys the lesults were not so readily demonstrable. After 

 the operation the "testicles" ascended to the upper region of the scrotum or 

 into the canal. After 2 to 3 weeks of testosterone treatment, the beginning of 

 descent was detected; the cord became longer, the organ approached the pouch. 

 In one case there was quite a complete descent, the "testicles" occupying the 

 middle region of the scrotum. In the 3 other animals, they descended 2 to 3 

 cm., lodging in the lower end of the canal or in the upper third of the pouch. 

 A hanging position, like that observed in the rat, was not attained in the 

 rhesus monkey; but the reasons for this may, perhaps, be merely the results 

 of surgical complications. By digital examination we had the impression of 

 the existence of connective bands which prevented complete descent; in one 

 case post-mortem examination showed in fact the presence of adhesions. The 

 differences in the surgical procedures in the two species must also be remem- 

 bered; in the rat it was possible to make a suprapubic approach, all the 

 tracts and adnexa of the testicle remaining untouched; in the rhesus monkey 

 it was necessary to make the incision in the scrotum or the canal which favored 

 the formation of adhesions which were further aggravated by the presence 

 of the foreign body. Nevertheless, we are enabled to conclude that there was 

 a visible effect of the hormonal treatment, although not so positive as in rats. 



Extirpation of the Scrotum: In normal rats, that is to say in those not sub- 

 jected to the experiment of substituting the testicular parenchyma with 

 paraffin, we observed that the operation of scrotal extirpation was no hin- 

 drance to the maintenance of practically normal position of the gonads, 

 which distended the adjacent nongenital skin (pi. 1, fig. 4). 



Discussion 



The results here reported show clearly that in rats, and very probably in 

 rhesus monkeys, testosterone is able to induce the descent of artificial paraffin 

 testicles. The action of the hormone is, therefore, extragonadic, independent 

 of any functional or morphological modification and of the dimensions or 

 consistency of the testicles. What then are the extragonadic conditions that 

 are necessary for the descent of the testicles? 



It seems that the most important are the following: 



permeability of the inguinal rings and canal; 



length and extensibility of the vas deferens, vessels, and smooth fibers of 

 the spermatic cord; 



development and relaxation of cremaster and dartos muscles; 



good development of scrotal pouch; 



sufficient abdominal pressure. 

 When we look for an active motile agent that might cause displacement in 

 the process of descent, we meet with difficulties. There is no muscular organ 

 which has its insertion on the testicle and another fixed extratesticular at- 



