354 



INTERNAL SECRETIONS 



performed their characteristic endocrine functions. Sand con- 

 cluded from these experiments that the antagonism of the two 

 kinds of gonads is not such as to involve a direct influence of one 

 on the other, but that there is in the normal organism some kind 

 of "immunity" against the heterosexual gonad. According to 

 Sand this "immunity" arises owing to the presence of certain 

 substances in the organism which are necessary for the normal 

 development of both gonads ; the gonad which is in its normal 



JriLr. I'zv. — Arnjicial ovariotesiis in the rat, 4 months after transplantation 

 of an infantile ovary into an animal 5 weeks old. Both ovary and testicle 

 have developed ; ripe follicles and corpus luteum in the ovarj% spermato- 

 genesis in most of the tubnles.^ — From Sand. 



place has more facility for obtaining these substances than the 

 engrafted gonad; the latter perishes on account of lack of the 

 necessary substances. When both glands are in the role of 

 grafts, or when an intratesticular implantation is made, both 

 glands are similarly conditioned, neither of them having a 

 preference. 



Certain observations have been made which seem to be 

 contrary to the statements of Steinach and Sand. W. Schulfz 



