104 GLANDS IN HEALTH AND DISEASE 



(the vas deferens) is cut off, thereby stopping the 

 production of the external secretion, and hence the 

 production of the reproductive elements; or the 

 genital glands are submitted to the effects of 

 X-rays, causing the less resistive reproductive ele- 

 ments to be destroyed. In either case the inter- 

 stitial cells are not only left intact, but actually 

 multiply and produce hormone in quantity (and 

 quality?) sufficient to rejuvenate (?) the organism. 

 There is still a third method, and that is to trans- 

 plant the gland from a vigorous animal to the one 

 under experimentation. We have already pointed 

 out that the transplantation of testicles has shown 

 that under such conditions, the reproductive ele- 

 ments disappear, but the interstitial cells continue 

 to thrive. Here again the organism is favorably 

 affected. 



All three methods point to the interstitial gland 

 as the source from which rejuvenation springs. 



With Steinach the question now arose as to which 

 of the three methods would be the one best adapted 

 for his purpose. In his experiments with human 

 beings he decided upon the first one the ligature 

 of the vas deferens as being the simplest to per- 

 form, and the one least likely to give rise to unfa- 

 vorable post-operative symptoms. "By stimulat- 

 ing the action of the interstitial gland at the ex- 

 pense of the generative function, it is Steinach's 

 idea to bring about a rejuvenation process in older 



