Lastly, we may mention a very singular species of laceration of the uterus, of which we know of but two cases, the one recorded by Mr. P. N. Scott, of Norwich, (_Med. Chir. Trans._ vol. xi.) the other which occurred under our own notice, where the whole os uteri separated from the uterus during labour.[114] In both cases, the os uteri presented a degree of unnatural rigidity, which was quite peculiar, and which in one case, defied repeated and active bleeding, as well as opiates. In Mr. Scott's case, the laceration took place during a violent pain, when the patient "felt something snap, the noise of which one of the attendants declared she heard." In the other case, the patient was not aware of any thing peculiar having happened: it was a first labour in the eighth month of pregnancy; the os uteri had dilated to nearly the size of half a crown, but would dilate no farther; the child had evidently been some time dead; the cranial integuments gave way from putrefaction, the brain escaped, the bones of the skull collapsed, and the bag of scalp protruded so far that we could lay hold of it, although the basis cranii had not passed. We were thus enabled to use more extractive force than we could have ventured upon with the crotchet: after a little effort, but without even a complaint from the patient, the head descended and passed through the os externum. "On the bed lay a disc of fibrous matter with a circular hole in the middle; in fact, the os uteri separated from the uterus to the extent of near half an inch, the edge of the laceration being as clean and smooth as if it had been carefully cut off by a knife." In both instances the patient recovered. Whether incisions into the os uteri for the purpose of effecting the necessary degree of dilatation would have been justifiable under circumstances of such unusual rigidity, does not belong to the present subject; for the consideration of this, we must refer to the FIFTH SPECIES OF DYSTOCIA. CHAPTER II. SECOND SPECIES OF DYSTOCIA. _Size and form of the child.--Hydrocephalus.--Cerebral tumours.-- Accumulation of fluid and tumours in the chest or abdomen.-- Monsters.--Anchylosis of the joints of the foetus._