CHANGES IN THE NON-PREGNANT UTERUS 87 



also has detected stroma tissue in the menstrual discharge 

 of the human female. This clearly shows that destruction is 

 not always confined to the epithehal layer. 



The blood poured out into the uterine cavity, and thence to 

 the exterior, does not usually clot, unless the amount be excessive. 

 This is due to the fact that the blood is considerably diluted 

 with mucus derived from the uterine glands. The glandular 

 activity is accompanied by an emigration of leucocytes which, 

 according to Blair Bell,^ are engaged in secreting calcium com- 

 pounds (see p. 69). The relative proportion of blood to mucus 



Fig. 10. — Section through mucosa of menstruating human uterus showing 

 bleeding into the cavity *. (From Sellheim.) 



in the fluid is usually said to increase from the commencement 

 of menstruation, until the discharge reaches its maximum, after 

 which it goes on diminishing until the flow ceases. 



The Stage of Repair. — This corresponds to Gebhard's period 

 of post-menstrual involution. After the flow has ceased, or 

 even a short time before it has quite ceased, regeneration of the 

 uterine mucosa begins. According to Westphalen,^ profuse 

 karyokinesis takes place in the tissue of the mucosa, which once 

 more increases in thickness, whereas Heape, as wiU be seen 

 later, describes a shrinkage as occurring in the regenerative 



1 Blair Bell, "Menstruation and its Relation to the Calcium Metabolism," 

 Proc. Hoy. Soc. Med., July 1908. 

 ^ Westphalen, loc. cit. 



