58o THE PHYSIOLOGY OF REPRODUCTION 



reality of this occurrence is supported by an observation which can 

 be made in many cases of Caesarian section ; in this operation it is 

 noticed that as long as the uterus remains outside the abdomen it 

 tends to bleed, but that as soon as it is dropped back bleeding 

 ceases. It is not the warmth of the abdominal cavity that checks 

 the bleeding, since it may continue when the uterus is wrapped in 

 warm towels outside the abdomen. But the mere fact of pulling up 

 the uterus opens out the concertina, as it were, and allows blood to 

 flow through the arteries. If the bladder is full at the end of labour, 

 the uterus is pushed upwards, and slight loss may continue until the 

 water is drawn off. As soon^ as the uterus is allowed to nestle down 

 into its normal position the bleeding stops." l 



The puerperal vaginal discharge is known technically as the 

 lochia. It varies considerably in amount in different individuals, and 

 changes in character as the puerperium proceeds, ceasing altogether 

 about the middle of the third week. For the first few days it 

 consists almost entirely of blood, which makes its way from the raw 

 surface of the uterus and from lacerations caused during delivery. 

 This is the lochia rubra. After three or four days it becomes paler, 

 owing to the dilution of the sanguineous discharge by mucous 

 secretion. This is called the lochia serosa. During the next three 

 days the normal colour of the lochia is brown. This change (from 

 pale pink to brow r n) is due to the fact that the normal acidity of the 

 vaginal secretion has by this time become re-established. Longridge 

 suggests that the brown colour is probably the result of the formation 

 of some such compound as acid hsematin. After about the tenth day 

 the lochia assumes a whitish or yellowish-white colour, owing to the 

 admixture of leucocytes and the cessation of the blood flow. It is 

 then known as the lochia alba. In many cases, however, traces of 

 blood may be observed for weeks, but the lochia alba consists mainly 

 of secretions from the vagina and cervix, together with leucocytes, a 

 few epithelial cells, fragments of decidual tissue, and crystals of 

 cholesterin. Micro-organisms are also present in the discharge, but 

 recent investigations have shown that the lochia obtained directly 

 from the uterine cavity does not contain bacteria, excepting in cases 

 where the uterus is the seat of infectious processes. 2 



The average quantity of the discharge has been computed by 

 Gassner 3 at 1485 cubic centimetres, or about 50 ounces. Giles 4 



1 Brock (Practitioner, January 1908) has recently expressed the opinion 

 that puerperal bleeding is chiefly venous, pointing out that the discharge is 

 usually very dark in colour. 



'-' Kltaig, Bakttriologie des <i<-nitftlkaital>'*. </<., Leipzig, 1907. 



3 Gassner, "Ueberdie Veranderungen des Korpergewichtes bei Schwangeren, 

 < Jfltarenden, und Wochnerinnen," Monatwhr. f. d'elmrtshuid?, vol. xv., 1862. 



4 Giles, "On the Lochia," Trim*. nl>*t,-t. ,W., vol. xxxv., 1897. 



