782 GENERATION. 



with a greater or less increase in the quantity of vaginal mucus, which be- 

 comes brownish or rusty in color and has a peculiar odor. At this time, 

 also, the breasts become slightly enlarged. This stage may continue for one 

 or two days, although in many instances the first evidence of the access of a 

 period is a discharge of blood. 



When the symptoms above indicated occur, the general sense of uneasi- 

 ness usually is relieved by the' discharge of blood. During this, the second 

 stage, blood flows from the vagina in variable quantity, and the discharge 

 continues for three to five days. With regard to the duration of the flow 

 there are great variations in diiferent individuals. Some women present 

 a flow of blood for only one or two days ; while in others the flow continues 

 for five to eight days, within the limits of health. A fair average, perhaps, is 

 four days. 



It is difficult to arrive at even an approximation of the total quan- 

 tity of the menstrual flow. Burdach estimated it at five to six ounces (about 

 150 to 175 grammes). According to Longet this estimate is rather low, the 

 quantity ordinarily ranging between ten and twelve ounces (300 and 350 

 grammes), occasionally amounting to seventeen ounces (500 grammes), or 

 even more. It is well known that the quantity is very variable, as is the 

 duration of the flow ; and the difficulties in the way of estimating the total 

 discharge are evident. 



The characters of the menstrual flow are sufficiently simple. Supposing 

 the discharge to continue for four days, on the first day the quantity is com- 

 paratively small ; on the second and third the flow is at its height ; and the 

 quantity is diminished on the fourth day. During this, the second stage, the 

 fluid has the appearance of pure, arterial blood, not coagulated, and mixed, 

 as has been shown by microscopical examination, with epithelium from the 

 vagina, cylindrical cells from the uterus, leucocytes and a certain quantity 

 of sero-mucous secretion. Chemical examinations of the fluid have not 

 shown any marked peculiarities, except that the quantity of fibrin is either 

 not estimated or is given as much less than in ordinary blood. 



The mechanism of the haemorrhage is probably the same as in epistaxis. 

 There is a rupture of small blood-vessels, probably capillaries, and blood is 

 thus exuded from the entire surface of the membrane lining the uterus and 

 sometimes from the membrane of the Fallopian tubes. The blood is then 

 discharged into the vagina and is kept fluid by the vaginal mucus. The 

 mucus of the body of the uterus is viscid and alkaline ; the mucus secreted 

 at the neck is gelatinous, viscid and tenacious, and is also alkaline ; the vagi- 

 nal mucus is decidedly acid, creamy and not viscid, containing epithelium 

 and leucocytes. . 



The third stage, that of cessation of the menses, is very simple. During 

 the latter part of the second stage the flow of blood gradually diminishes. 

 The discharge becomes rusty, then lighter in color, and in the course of 

 about twenty-four hours, it assumes the characters observed in the intermen- 

 strual period. 



When the menstrual flow has become fully established there is no very 



