98 GLANDS IN HEALTH AND DISEASE 



to the elaboration of an internal secretion, and the 

 further fact that with old age the interstitial cells 

 become fewer and smaller, must have suggested to 

 physiologists a possible connection between old age 

 and the interstitial glands. To test out such a 

 possibility has led to a number of extremely inter- 

 esting experiments. Kesearch workers following 

 Brown-Squard showed that the addition to the 

 food, or the injection into the blood, of testicular 

 extracts, failed to change castrated into normal 

 animals, or old animals into young ones. The rea- 

 son for this is not easy to give, unless we assume 

 that a chemical process involving an extraction of 

 the hormone from the interstitial gland an opera- 

 tion which is usually carried out by triturating the 

 gland with sand and water, filtering and using the 

 filtrate causes an alteration of the hormone. 



Dr. Voronoff remarks that "the injections of 

 testicular juice have not had the result which 

 Brown-Squard expected from them, because the 

 glandular extracts undergo rapid changes, do not 

 contain the whole of the product of the internal se- 

 cretion, and are even, at times, toxic." * This is 

 obviously not true of some of the other ductless 

 glands, notably the thyroid. 



Next came the suggestion that a much better 

 method than that of injection of gland would be the 



*See Life by Serge Voronoff. E. P. Dutton & Company, New 

 York. 



