Where some time has elapsed without any symptoms of contraction coming on, we may excite the uterus by circular friction of the abdomen, fanning the face, or by sprinkling a little water upon it, &c.: if, however, the uterus is hard and yet the placenta not within reach, we may pull slightly at the cord, pressing it at the same time back with the fore-finger into the hollow of the sacrum; we thus bring it down in the direction of the pelvic axis, and generally succeed in moving it into the vagina. No violent effort should be made, as this would probably tear it off from its insertion into the placenta, but, by keeping a gentle pressure upon it, the placenta will slowly pass through the os uteri, and then come away without farther difficulty. Following the axis of the vagina, we now guide it downwards and forwards; and when it approaches the os externum, it should be seized with the finger and thumb, and rotated several times: the membranes are thus twisted into a rope, and are less liable to be torn in separating from the uterus. The uterus being now completely emptied, contracts into a hard ball of about the size of a child's head. If, however (whether before or after the expulsion of the placenta) the uterus grows soft and swells, if the patient becomes pale and restless, and complains of faintness, sickness, load at the præcordia, darkness before the eyes, &c. we may be sure that hæmorrhage is going on. We refer to the chapter upon uterine hæmorrhage for the measures to be adopted. _Twins._ Where there are twins, the above rules for ensuring the safe expulsion of the placenta require to be still more strictly observed: the uterus has been more distended, the mass of placenta is larger, and is attached to a much greater extent of surface than where there has been only one child: hence there is not only a greater liability to hæmorrhage, but if it does take place, will probably be much more dangerous. We cannot be too cautious how we extract the placentæ of twins: from the size of the mass, the uterus remains larger, and therefore less contracted: hence, if we venture to pull at the cord before being able to reach the placenta with our finger, we shall feel it yield; but this is not from the placentæ being detached and coming away, but from the fundus itself being pulled down with it--a state which would rapidly pass into inversion if the force were continued. In order to detach the mass more equally, we should twist the two cords together; by so doing there is less danger of their giving way. The same rotating movement should be used when the placentæ approach the os externum; the two bags of membranes are thus twisted together, and come away entire: if this be not attended to, the membranes are torn, portions of them are left adherent to the uterus, and come away some days afterwards in a half putrid state producing a fetid discharge, and sometimes considerable fever.