THE OEGANS OF KEPEODUCTION 103 



himself to elucidate. His idea was to transplant 

 the sexual glands of young rats to the system of 

 old ones to put "new wine into old bottles." 

 Much preliminary work was necessary in order to 

 determine the conditions for developing healthy 

 breeds of rats. The extensive vitamine studies, in 

 which rats are very largely employed, had then 

 hardly begun ; otherwise such difficulties could have 

 been avoided. Steinach succeeded not only in im- 

 proving the general condition of the old rats, not 

 only in renewing the sex instinct, but actually in 

 prolonging the life of the animal. "Three weeks 

 after the operation the whole behavior changed* 

 the rat (an old one) began to keep its head erect, 

 came forward from its hole, paid a lively interest 

 toward the outer world, and its hair began to 

 grow smooth and shiny. When another male rat 

 had been let into its cage it attacked him immedi- 

 ately, and when a female rat was let in, it eagerly 

 performed the sexual function, and as only one 

 vas deferens (see subsequent paragraph) was li- 

 gated, the coitus was successful. The young of the 

 female fecundated by the rejuvenated rats thrived 

 well, and propagated further." 



Our discussion of the interstitial glands has al- 

 ready shown that in the investigations of this duct- 

 less gland, one of three methods in operating tech- 

 nique may be employed : the duct from the testicle 

 connecting the testis with the ejaculatory tube 



