82 



THE PHYSIOLOGY OF REPRODUCTION 



proportion of blood to mucus 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. 

 Oliver^ has made a quantitative examination of the menstrual fluid 

 obtained from a girl with an imperforate hymen. After making an 

 incision he withdrew VO oz. : 87 IS per cent, was water; of the 

 remainder 4-98 per cent, was ash and 95-02 organic material, including 

 12'49 serum albumen, 16"56 globulin, 3'37 mucin, and a trace of fat. 

 The ash contained sodium, potassium, calcium, phosphorus, and iron ; 

 and the salts, chlorides, carbonates, phosphates, and sulphates. 



The Stage of B^pair. — This corresponds to Gebhard's period of 



Fig. 11. 



-Section througji mucosa of menstruating human uterus, showing 

 bleeding into the cavity *. (From Sellheim.) 



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 will be seen later, describes a shrinkage 

 as occurring in the regenerative stage in monkeys. Wyder,* who 

 believed in the partial destruction of the uterine stroma, concluded 

 that this was restored by a hyperplasia of cells in the interglandular 

 tissue of the deeper layers of the mucous membrane, and that the 

 lost epithelium was regenerated from the epithelium of the glands. 

 Similar views have been held by other writers. 



Those authorities who hold that the destruction is practically 



1 Oliver, " New Aspects of Menstruation,'' New York Med. Jour., November 

 1920. 



' Westphalen, loo. cit. 



3 Whitridge Williams, loc. cit. 



