The passage of the head is not the only moment of danger to the perineum, for laceration is even still more liable to be produced during the expulsion of the shoulders; any slight rupture of the anterior edge is now apt to be converted into a considerable laceration, unless the support be continued until the thorax be expelled. We have already stated that the frænulum perinei is generally torn through in the first labour; but the laceration ought not, if possible, to extend farther, because serious injury may be produced either to the vagina, or even to the sphincter rectum. To say, however, that laceration of the perineum need never happen, would be preposterous; because cases every now and then occur, where, from the contracted and unyielding state of the os externum, and from the size of the child, it is nearly impossible that the perineum can escape without injury; fortunately, although considerable lacerations are by no means uncommon, they are seldom observed to extend into the sphincter ani, the direction of the rent being usually to one side. Under the ordinary circumstances of perineal laceration, little more than mere attention to cleanliness is required; for the parts contract so astonishingly after labour, that what was a wide rent of an inch and a half long, in a couple of days will be scarcely more than two or three lines in length. Rest, great cleanliness, and gentle-relaxed bowels, constitute the chief treatment. _Treatment of perineal laceration._ Where, however, the laceration extends into the rectum, the case becomes exceedingly troublesome and difficult to cure, and the patient is liable to be rendered a miserable object for life; for the action of the sphincter being entirely destroyed, she is unable to retain fæces or flatus in the rectum; besides which, from the injury to the posterior wall of the vagina, prolapsus uteri is an almost certain consequence. In these cases the slightest movement of the thighs upon each other alters the position of the lips of the wound, and thus tears it open afresh, so that at length the edges of the wound become callous and refuse to heal. A great deal in these cases depends upon the patience and good conduct of the patient herself; for if she have the resolution to lie perfectly still for at least a week, she will have every chance of a perfect cure. If there be much swelling of the edges, and a disposition to slough, a warm poultice of chamomile flowers should be applied, and the bowels kept in a nearly liquid state by gentle and repeated doses of salines, in order to prevent distension of the rectum when the evacuation is passing; she should preserve the supine posture, and have her knees confined together by a piece of tape, as is done with patients after the operation of lithotomy. Straps of adhesive plaster are seldom or never of any use, but if the rent be very severe a suture or two may be required. The great fault in applying these means for bringing the