REPRODUCTION. 



859 



is swollen and congested. From it are derived the blood and epithe- 

 lium of the menstrual flux. By some authorities it is claimed that 

 the entire uterine mucous membrane is exfoliated at every flux, to 

 be regenerated in the interim. 



It has been found by observers that congestion of the ovary 

 coincident with sexual intercourse is capable of rupturing Graafian 

 follicles and so liberating ova. From this it is reasonable to sup- 

 pose that the congestion and high tension of the generative organs 

 during the time of menstruation would surely accomplish the same 

 end. 



Fig. 391. Uterus at Menstrual Period, Showing Congested Area 

 and Destruction of Mucous Membrane. (Photomicrograph by 

 GRAMM.) (GILLIAM.) 



The usual period of a f emale's life during which she menstruates 

 is from puberty (from the thirteenth to the fifteenth year) to the 

 climacteric, or menopause (about the forty-fifth year). Its cessation 

 at the latter period denotes the end of the childbearing period. 



The cessation of menstruation may be abrupt or gradual, and 

 is frequently accompanied by disturbance of the physical and the 

 mental functions. Removal of the ovaries usually causes menstru- 

 ation to cease; occasionally, however, menstruation persists. If 

 after the ovaries are removed and menstruation has ceased, an ovary 

 is transplanted, then menstruation returns, 



