THE REPRODUCTIVE ORGANS. 



759 



have been removed by operation. Some instances have been recently 

 recorded, indeed, of a sanguineous discharge occurring periodically from 

 the vagina after both ovaries have been previously removed for disease; 

 and it has been inferred from this that menstruation is a function inde- 

 pendent of the ovary : but this evidence is not conclusive, inasmuch as 

 it is possible that portions of ovarian tissue were left after the operation. 

 Source and Characters of Menstrual Discharge. The menstrual dis- 

 charge is a thin sanguineous fluid, having a peculiar odor. It is of a 

 dark color, and consists of blood, epithelium, and mucus from the 



Fig. 454. 



Fig. 455. 



Fig. 456. 



Fig. 454. Diagram of uterus just before menstruation; the shaded portion represents the 

 thickened mucous membrane. 



Fig. 455. Diagram of uterus when menstruation has just ceased, showing the cavity of the 

 uterus deprived or mucous membrane. 



Fig. 456. Diagram of uterus a week after the menstrual flux has ceased: the shaded portion 

 represents renewed mucous membrane. (J. Williams.) 



uterus and vagina. The menstrual flow is preceded by a general engorg- 

 ment of all the pelvic organs with blood. The cervix and vagina become 

 darker in color and softer in texture, and the quantity of mucus secreted 

 by the glands of the cervix and body is increased. The uterine mucous 

 membrane is swollen and the glands are elongated and tortuous. The 

 discharge of blood, the source of which is the mucous membrane of the 

 body of the uterus, is probably associated with uterine contractions. 

 There is great difference of opinion as to whether or not any of the 

 uterine mucous membrane is normally shed during the process of men- 

 struation. John Williams believes that the whole of the mucous mem- 

 brane of the body of the uterus is thrown off at each monthly period, 



