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HANDBOOK OF PHYSIOLOGY. 



of ova, yet the preseace of the ovaries seems necessary for the perform- 

 ance of the function; for women do not menstruate when both ovaries 

 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 tisues 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 ute- 



FIG. 43G. 



FIG. 437. 



FIG. 43C 



FIG. 436. Diagram of uterus just before menstruation; the shaded portion represents the thick- 

 ened mucous membrane. 



FIG. 437. Diagram of uterus when menstruation has just ceased, showing the cavity of the 

 uterus deprived of mucous membrane. 



FIG. 438. Diagram of uterus a week after the menstrual flux has ceased; the shaded portion 

 represents renewed mucous membrane. (J. Williams.) 



rus and vagina, serum, and the debris of a membrane called the decidua 

 menstrualis. This membrane is the developed mucous membrane of 

 the body of the uterus. It does not extend into the Fallopian tube or 

 into the cavity of the cervix. It attains its highest state of development 

 in the unimpregnated organ just before the commencement of a catame- 

 nial flow (Fig. 436). If impregnation take place, it becomes the decidua 

 vera; if impregnation fail, the membrane undergoes rapid disintegration; 

 its vessels are laid open and hemorrhage follows. The blood poured out 

 does not coagulate in consequence partly of the admixture already men- 



