CYCLIC CHANGES IN UTERUS AND OVARIES. 35 



Several months after castration, the wall of the uterus is thin; 

 the surface epithelium is cuboidal or low cylindrical. There are 

 mitoses present in the surface epithelium; their number varies. 

 The glands are small and without mitoses; the connective tissue 

 of the mucosa is fibrillar, contains small nuclei and is somewhat 

 richer in nuclei directly beneath the epithelium than in the 

 deeper parts of the mucosa. Two to three weeks after castration 

 we find also low cuboidal or low cylindrical epithelium covering 

 the mucosa of the uterus; no mitoses are present in the gland 

 cells which are all small. The connective tissue is fibrillar and 

 the connective tissue nuclei are small and without mitoses. 



We see that after total extirpation of the ovaries the mucosa 

 of the uterus becomes similar to the mucosa of the pregnant 

 uterus in a non-pregnant horn. Gradually all the layers of the 

 uterine wall seem to become thinner. 



If we extirpate the ovaries within the first twenty-four hours 

 after copulation and examine the uterine mucosa six or seven 

 days after copulation we find the surface epithelium usually low 

 cuboidal or cylindrical; it may, however, be somewhat higher; 

 there are mitoses present in the surface epithelium; the glands 

 have low epithelium and are usually without mitoses. In the 

 connective tissue no cell-layer developed and no mitoses are 

 visible. We find, therefore, here a similar result as after ex- 

 tirpation of the corpora lutea, namely, inhibition of the connec- 

 tive tissue proliferation and at the same time continued mitotic 

 proliferation in the surface epithelium, which is lacking at this 

 period in the normal uterine cycle. The extirpation of the 

 ovaries acts in this respect principally through the lack of the 

 corpora lutea which castration entails. In one case, however, 

 in which fresh corpora lutea of the guinea-pigs were injected into 

 a guinea-pig which had been castrated sixteen and a half hours 

 after copulation, five days after castration a few mitoses were 

 found in the connective tissue of the mucosa. We must leave 

 it at present undecided whether the injection of the corpus luteum 

 substance produced this result. 



If we extirpate within the first twenty-four hours following 

 copulation the ovaries and make incisions into the uterus six 

 to seven days after copulation we find on examination ten days 



