CHANGES IN THE NON-PREGNANT UTERUS 93 



plete 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 equahsa- 

 tion to the fact that the ruptured vessels to which the leucocytes 

 adhered in the earKer 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 ; 

 (2) red blood corpuscles ; (3) masses of stroma tissue and 

 epithehum, both from the hning of the uterine cavity and from 

 the glands, and squamous epithehum from the vagina ; and 

 (4) leucocytes together with isolated nuclei of broken-down 

 epithehal 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 men- 

 struation after remaining some time in the uterine cavity. 



VIII. The Recuperation Stage. — The changes which occur 

 during this stage are described by Heape as consisting of five 

 processes, as follows : — 



(1) The re-formation of the epithehum. 



(2) The reduction of the blood supply. 



(3) The formation of new and recuperation of old 



blood-vessels. 



(4) The changes which take place in the stroma. 



(5) The behaviour of the leucocytes. 



(1) The new epithehum is formed, according to Heape, partly 

 from the epithehum of the glands, but partly from the underlying 

 stroma. The latter is described as a tissue of very primitive 

 characteristics, and the re-formation of the epithehum is re- 

 garded as a speciahsation of cells belonging to a layer which, in 

 the embryo, gave rise in the same way to similar epithehal 



