44 LEO LOEB. 



15. The existence of pregnancy in one horn of the uterus 

 prolongs markedly the life of placentomata produced in the other 

 horn. 



1 6. For certain phases of the cyclic changes of the uterus the 

 presence, for other phases the absence, of a functionating corpus 

 luteum is necessary; but certain other ovarian structures (prob- 

 ably mature follicles and not the so-called interstitial gland) are 

 required for the latter phases. In addition the absence of preg- 

 nancy (and probably of living placentomata) is a condition for 

 the typical course of the cyclic changes in the uterine mucosa. 



