i84 INTERNAL SECRETIONS OF THE OVARY 



fertilized ovum to the uterine mucosa, and also for the subse- 

 quent maintenance of foetal nutrition. Fraenkel's work 

 was confirmed and extended by the experiments of Ancel and 

 Bouin (29-32) on the same animal. This dependence of the ovum 

 on the influence of the corpus luteum for attachment is clearly 

 correlated with the post-ovulative changes which occur in the 

 uterine endometrium. These changes may be either very 

 obvious histologically, as in the dog, ferret, and rabbit, or they 

 may be less perceptible and indicated mainly by physiological 

 sensitivity, as in the guinea-pig. After sterile copulation in the 

 rabbit and the consequent formation of the corpora lutea, the 

 uterus shows growth, vascularization, and particularly glandular 

 increase in a manner comparable to the growth changes during 

 pregnancy. During this pseudo-pregnant period the six folds of 

 the rabbit endometrium proliferate and become so infiltrated with 

 convoluted glands that in cross section they present a fern- 

 like appearance. This typical change during pseudo-pregnancy 

 has been definitely shown to be under the control of the corpus 

 luteum. Thus, Ancel and Bouin (31), by ablation of the 

 corpora lutea after ovulation, prevented the typical pseudo- 

 pregnant changes, while O'Donoghue (478), having produced 

 luteal tissue experimentally by puncturing the Graafian follicles, 

 was able to bring about the pseudo-pregnant changes without 

 the preliminary act of true ovulation. In the dog similar post- 

 oestrous activity takes place in the uterus, and there can be 

 little doubt that this is due to the activity of the corpus luteum, 

 though experimental evidence is lacking. In the same way 

 post-oestrous changes occur in Dasyurus, and Corner (122) has 

 described in the uterus of the sow a certain amount of post- 

 ovulation activity. 



Production of deciduomata. In other mammals the actual 

 histological changes are less obvious, but, nevertheless, in many 

 cases it has been shown that a peculiar sensitivity to mechanical 

 irritation is present. This reaction of the post-oestrous uterine 

 mucosa was originally shown by Loeb (380) in the guinea-pig. 

 This author, by cutting the endometrium, was able to cause the 

 production of large blocks of decidual cells, to which the name 

 placentomata or deciduomata has been given. Loeb (382-3) 

 found that this sensitivity of the post-oestrous uterus v/as 



