CHANGES IN NON-PREGNANT UTERUS 87 



described in the uterus of the dog at a corresponding stage in the 

 cycle. Degenerative changes were noted in many of the epithelial 

 cells, and also in some of the stroma cells, certain of which were 

 seen scattered beneath the remains of the epithelial lining. The 

 stroma below the lacumu was observed to contain normal as well 

 as shrivelled tissue, but the deeper parts appeared to undergo very 

 little alteration. 



VII. The Formation of tlw Menstrual Clot. At this stage Heape 

 describes "a severe, devastating, periodic action." The entire 

 superficial epithelium, portions of the glands or even a whole gland, 

 and a part of the stroma, with broken-down blood-vessels and 

 corpuscles, are torn bodily away, " leaving behind a ragged wreck of 

 tissue, torn glands, ruptured vessels, jagged edges of stroma, and 

 masses of blood corpuscles, which it would seem hardly possible to 

 heal satisfactorily without the aid of surgical treatment." Heape is 

 in no doubt as to the extent of the denudation, differing thus from 

 those writers referred to above, who believe that the destructive 

 process in the human female does not extend beyond certain portions 

 of the superficial epithelium. The cast-off mucous membrane is 

 termed by Heape the mucosa menstrualis. The deeper tissue under- 

 goes no change, the blood-vessels therein being still possessed of 

 complete walls, but these are larger and more numerous than before. 

 There is no extravasated blood in this region. The proportion of 

 leucocytes in the vessels was observed to be about three per cent, 

 of the corpuscles present, while those on the surface were estimated 

 to comprise about 2'5 per cent, of the total number of corpuscles. 

 Heape ascribes this comparative equalisation to the fact that the 

 ruptured vessels to which the leucocytes adhered in the earlier 

 stages, are themselves cast off, and their contents mingled with the 

 extravasated blood. The supply of leucocytes in the vessels, however, 

 is. well maintained. 



The menstrual discharge is described as consisting of (1) a viscid, 

 stringy, opaque white fluid derived partly from the blood-serum and 

 partly from the secretion of the uterine glands, containing numerous 

 small granules which have their origin in the broken-down plasmodium 

 of the uterine mucosa ; ('!} red blood corpuscles ; (o) masses of stroma 

 tissue and epithelium, both from the lining of the uterine cavity and 

 from the glands, and squamous epithelium from the vagina ; and (4) 

 leucocytes together with isolated nuclei of broken-down epithelial 

 and stroma cells. The menstrual clot is composed very similarly, 

 containing a mass of corpuscles together with fragments of uterine 

 tissue. It is expelled at the end of menstruation after remaining 

 some time in the uterine cavity. 



