The causes of puerperal disease which have been enumerated by Cruveilhier, apply almost solely to those inflammatory affections of the puerperal state which do not depend upon a vitiated state of the circulation, but “are derived from the changes induced by parturition, and are dependent on,
“1. The organic changes induced by pregnancy.
“2. Those induced by the act of labour.
“3. Those consecutive of labour.
“1. Pregnancy:—the hyperthrophy of the uterus; the enlargement of the ligamenta lata; the traction on the peritoneum of the neighbouring organs; the extraordinary development of the arteries, veins, and lymphatics.
“2. Changes induced by labour:—bruising of all the soft parts—they appear raw.
“3. Changes after labour:—the woman presents the faithful picture of one who has undergone a serious surgical operation. The internal surface of the womb may be compared to a vast solution of continuity; the whole of the mucous membrane has been altered by the inflammation, of which it has been the seat; the gaping veins are like the open mouthed vessels of an amputated limb.
“Except just at the inner surface of the cervix uteri, there is no mucous membrane at all; but the muscular tissue of the uterus is every where exposed. This, therefore, like the stump, is to be covered by a new membrane.
“This process of reparation is accompanied by a traumatic fever, called milk fever. Like the fever from wounds, it has its period of incubation, varying in various individuals: it lasts about twenty-four hours, and vanishes on the third day.
“As in amputation, a false membrane covers the stump, and precedes cicatrisation, so the inner surface of the womb is first covered with a false membrane before it is cicatrised. If there be no lochial discharge, there is union by the first intention, as in the stump where there is no discharge: this is the rarest of all cases.