50 INTERNAL SECRETIONS OF THE OVARY 



Pregnancy. During the whole of pregnancy the smear 

 consists of a few nucleated epithelial cells and leucocytes. Much 

 mucus is present all the time, and blood appears in both the rat 

 and mouse at about the twelfth day owing to uterine haemorr- 

 hage (the ' placental sign ' of Long and Evans). 





c.e. 



Fig. 24. — Vagina of Mouse during (Estrus, showing 

 cornification of the epithelium. 



C.e. cornified epithelium sloughed off into the lumen. 



Pseudo-pregnancy . Following sterile copulation, i.e. during 

 pseudo-pregnancy, the vaginal smear is of the dicestrous type, 

 except that much mucus is present. About three days before 

 the next oestrus is due a smear containing blood is usually 

 obtained. 



In the rat the vaginal cycle is similar to that of the mouse. 

 Long and Evans (425) summarize the changes during the cycle 

 in the rat as in Table 3. 



The nature of the leucocytes in the vaginal smear has been 

 studied by Post (518) and Guttmacher (254). 



