OVULATION AND MENSTRUATION. 457 



or of any kind of influence from the male ; but it is possible 

 that, as held by many authorities, the discharge of ova, though 

 in no way dependent on sexual intercourse, may yet be hastened 

 by this. 



4. Menstruation. 



Menstruation is the periodical discharge from the uterus of 

 a certain amount of blood, mixed with mucus from the uterine 

 glands, and with epithelial and connective-tissue cells, derived 

 from disintegration of the mucous membrane of the uterus 

 itself. 



There is a close connection between menstruation and ovu- 

 lation. Both processes commence at puberty, and last through- 

 out the child-bearing period. They both recur periodically ; 

 and, further than this, the intervals are the same, and the two 

 processes occur, as a rule, simultaneously. The true nature 

 and extent of the connection between the two will be discussed 

 after the nature of the menstrual process has been considered 

 more fully. 



During the period of pregnancy, that is, during the whole 

 time that an ovum or embryo is -developing within the uterus, 

 menstruation ceases, recommencing six or seven weeks after the 

 birth of the child. The normal occurrence of the menstrual 

 periods may also be affected by a variety of accidental or 

 pathological conditions, for the consideration of which reference 

 must be made to works dealing with obstetrics. 



Menstruation, i.e. the actual discharge from the uterus of 

 blood and other matters, is not an isolated process, but is the 

 terminal act of a series of changes, which occur at regular 

 intervals in the walls of the uterus, and of which the sequence is 

 as follows. 



In the quiescent condition the uterus is lined by a smooth 

 mucous membrane, of a soft, spongy consistence, and pale red 

 colour. It consists of a single layer of ciliated epithelial cells, 

 resting on a very delicate basement membrane, beneath which 

 is the connective-tissue layer of the mucous membrane. This 

 latter is about 1'5 mm. in thickness, and consists of connective 

 tissue, with very numerous connective-tissue cells, and traversed 

 by irregularly arranged muscle fibres. It is attached by its 

 outer surface to the muscular Avail of the uterus. 



