102 GLANDS IN HEALTH AND DISEASE 



new wine should not be poured into old bottles! 



Prior to 1910, when Dr. Steinach published the 

 first of his experiments, it had already been known 

 that the generative apparatus consists of an inter- 

 nal and external secretion, and there were even 

 then indications that the hormone, or hormones, 

 produced by the internal secretion (in the inter- 

 stitial cells) controlled sex characteristics. Pro- 

 fessor Steinach wished first to convince himself 

 that what was generally believed had foundation 

 in fact: that the internal secretion actually con- 

 trolled sex characters. With this in view he cas- 

 trated a number of male rats and guinea-pigs and 

 planted ovaries under the skin. The animals de- 

 veloped marked feminine features: their breasts 

 and nipples increased in size and they were sought 

 by the males. Previous experiments on the trans- 

 plantation of the testes had shown that though the 

 reproductive glands proper decayed and the inter- 

 stitial glands did not, yet the sex desire remained. 

 These experiments indicated two things : first, that 

 the generative glands have much to do with deter- 

 mining the sex of the animal; secondly, that the 

 portion of the glands particularly responsible is 

 the interstitial gland. 



Old age. As already pointed out, the work of 

 Brown- Sequard suggested a connection between 

 the decay of the genital glands and the onset of old 

 age. This was the next problem that Steinach set 



