The “flooding” as it is called by the laity, is most apt to come on either immediately or within an hour or so after labor. If it comes on _after_ the first twenty-four hours, it is called secondary hæmorrhage. Such predisposing causes as over-distention from twins may be present, but the hæmorrhage may follow a perfectly easy and apparently normal labor so suddenly and so profusely that the woman may die in half an hour. There are four causes for post partum hæmorrhage: namely, (a) uterine exhaustion (atonia uteri); (b) mechanical obstacles to retraction, such as clots or retention of pieces of placenta or membrane; (c) and lacerations of some part of genital passage, such as the vulva, vagina, cervix, or lower uterine segment; and (d) the systemic condition known as hæmophilia. “Bleeders” (hæmophilias) are women whose blood lacks coagulability, owing to the absence of fibrin-producing elements. Post partum hæmorrhage is usually an external hæmorrhage, but the woman may bleed to death into her own uterus. Besides the external signs, the patient may show the symptoms of acute anæmia, such as the rapid pulse, hurried, shallow respiration, pallor, cold sweat, yawning, dizziness, etc. Nearly all these cases can be saved by prompt recognition and efficient _treatment_. The first step is to grasp the uterus. If the hæmorrhage is due to a tear low down, the uterus may be hard, but generally it is relaxed and requires vigorous massage with both hands before it shows any signs of contraction. In the absence of the doctor, the nurse must know how to undertake this maneuver. The uterus, after labor and especially when relaxed, is sometimes difficult to identify and the nurse can only make deep massage in the pelvis until the organ responds and its hard globular mass can be appreciated. As soon as the uterus contracts, clots and contained blood are expelled, and in many cases its bleeding ceases at once. (See Conduct of Third Stage, p. 149.) It may be necessary to keep the uterus contracted by manual massage in this way for several hours. As soon as possible, the nurse, or someone whom she directs, prepares a hypodermic of pituitrin—10 to 15 ♏︎. An injection of ergot may follow because its effect is more lasting than pituitrin. Next, a hot douche is made ready and the materials for packing the uterus are assembled. When the doctor arrives, he sterilizes his hands, puts on gloves and introduces two fingers or the whole hand into the uterus to remove clots or any retained fragments of placenta. The hot intrauterine douche may follow, and if the contraction is not firm and the hæmorrhage checked, the uterus must be packed with gauze. If hæmorrhage comes from cervix, it should be grasped with long forceps, pulled down, and sutured. If from perineum, pack first, and afterward sutures may be introduced.