DIOESTROUS CYCLE IN THE GUINEA-PIG 247 



Large vacuoles are to be seen between the epithelial cells, and 

 these are probably produced by the dissolving power of the 

 leucfocytes. Under the destroyed epithelium haematomata are 

 to be seen in several places, produced by the congestion of the 

 peripheral capillaries in the stroma. A leucocytosis somewhat 

 similar to the above has been described by Heape, Konigstein, 

 Blair-Bell and others in the uteri of several mammals. 



The vagina of the guinea-pig also shows analogous conditions 

 as illustrated in figure 17. 



The broken down epithelium remains until the regeneration 

 process begins. The reparation starts from the necks of the 

 uterine glands which have remained intact during the entire 

 process of destruction. A few leucocytes are to be seen be- 

 tween the epithelial cells of the uterine glands but this small 

 number apparently passes through the epithelium into the duct 

 without injuring the epithehal cells. The stage of reparation 

 corresponds to the fourth stage, that is, to the period when blood 

 is sometimes seen in the vaginal fluid, see smear figure 9. This 

 is not difficult to explain since regeneration and the falling off 

 of the degenerated epithelium take place at the same time. 

 Regeneration of the uterine epithelium before the oestrous flow- 

 had ceased has been reported in other mammals. 



After examining a number of specimens, one may get t;he im- 

 pression that the new epithelium growing out from the neck of 

 the glands tends to push off the old degenerate epithelium, as it 

 becomes detached from the wall of the uterus. Figures 18 and 

 19 show this condition where the new and the old epithelium 

 are still existing in close proximity, the one growing out from 

 the gland, the other breaking away from the wall of the uterus. 

 In figure 19, this condition is more adva;nced and one sees th.e 

 old epitheUum partly detached from the wall of the uterus. 

 Generally the epithelium falls off still connected with pieces of 

 the stroma, which also seems to be destroyed to some extent 

 during every heat period. These masses of epithehal cells are 

 commonly found in the vaginal fluid. When the epithelium 

 falls awav the haematomatia are uncovered and the blood con- 



