edges of the wound together is the attempting to unite them throughout their whole length; for by so doing the tension of the parts is increased, and therefore there is less disposition to unite; and even if we succeed in effecting complete union of the whole wound, the perineum is so contracted and unyielding from the cicatrisation, that it can scarcely escape a repetition of the injury in succeeding labours. It is, therefore, much better that we should content ourselves with uniting merely the posterior half of the laceration; the parts heal much more readily, and the os externum is left of a sufficient size to escape all danger of laceration on future occasions. Where the edges have become callous and refused to unite, they require to be pared and brought together again; this, however, does not always succeed, and the case becomes very difficult and protracted: under these circumstances, the treatment adopted by Dr. Dieffenbach, of Berlin, is well worthy of attention. Having pared off the callous edges of the wound, he brings them into the closest opposition by transfixing them with needles in several places, as is done for the operation of hare-lip; and in order to isolate the wound as much as possible from the surrounding parts, and prevent any tension, he makes a free incision through the integuments, parallel with the wound, at a little distance from it, and nearly of the same length; by this means, every cause which might tend to separate the edges is removed; whilst the parallel cuts, being fresh incised wounds, soon close by granulation.[68] It sometimes, although rarely, happens that the perineum, instead of being torn from before backwards, is perforated through its centre by the head, so that the child is not born through the os externum, but through a lacerated opening in the body of the perineum. This accident may arise from a variety of circumstances: the direction of the pelvic outlet may be faulty, or the inclined plane formed by the lower part of the sacrum, by the sacro-sciatic ligaments, &c. may be insufficient to guide the head forwards under the pubic arch; or the perineum may be unusually broad; in which cases the power of the uterus being directed against the centre of it, the head becomes enveloped in a bag of protruded perineum; and if the pains are violent, and the head not properly supported, it at length bursts its way through the centre without even injuring the frænulum. The treatment of this form of ruptured perineum is the same as that of the more common species; the bowels must be kept open, and a fomentation of chamomile flowers applied to the wound, which, from the gradual contraction of the surrounding parts after labour, diminishes remarkably, so that in the course of a short time it will have entirely or nearly closed.[69]