THE TESTICLE AND THE OVARY 



375 



and 620). The changes were not excited by the presence of ova in 

 the uterus, since they took place when the lower part of that organ 

 was ligatured off' so as to prevent the passage of the ova. On the 

 other hand, if the ovaries were extirpated decidnomata could not l>e 

 produced. If the corpora lutea were as far as possible burnt out 

 of the ovaries by the electric cautery, deciduoniata were not genera llv 



-i. 



FIG. 97. Experimentally produced placenta of pseudo-pregnant rabbit ; section 

 of uterus showing connective tissue forming decidual cells which enclose 

 vessels. (From Hammond.) 



produced; but owing to the difficulty <>f properly pet I'm -ming these 

 experiments, the results were not quite conclusive. Lastly, when 

 pieces of uterus were transplanted into the subcutaneous tissue, 

 deciduoniata were formed in the grafted pieces. It is concluded. 

 therefore, that the ovaries at certain periods after ovulation (and 

 probably the corpora lutea) elaborate a predisposing substance in the 

 presence of which indifferent stimuli (traumatiMns) may produce 

 deciduoniata. Hammond has obtained similar results with rabbits.' 



1 Hammond, !<-. cit. 



