Among the special causes which often paralyze the action of the womb, may be mentioned a full habit of body, great distention of the uterus from accumulations of fluid, and extreme thickness of the membranes. In some cases in fact, the membranes will be so strong that the most violent contractions fail to break them, and the uterus completely exhausts itself to no purpose. It is in such cases as these, when the mouth of the womb is fully dilated, that the accoucheur should rupture the membranes artificially. This is usually done with the finger nail by pinching them. Some practitioners however use a pointed instrument, or a sharp quill; but there is always more or less danger of injuring the child or the mother by such means. The best time for breaking them is during a strong pain, when they are fully distended. The mere scratching, or pushing on them will frequently suffice. I have known cases however in which they were so strong that an instrument was actually necessary to open them. The death of the infant also seems sometimes to check uterine contraction, though probably not from the mere circumstance of its being dead, but because the womb suffers from the same morbid cause which produced its death. Any strong moral impression may also produce the same state of things. Thus in some females the womb will instantly cease its contractions, and the labor be arrested, from _fright_, or from strong repugnance to somebody, or something, in the room. Instances have been known of women being so alarmed on first seeing the accoucheur, or so displeased because he was not the one they wished, that the uterine efforts immediately ceased, and could not be again brought on for a long time. The presence of some person who is a subject of dislike may also have a very prejudicial effect, and if this is known they should be immediately removed. Dr. Merriman tells us of a female who was seized with a fit, from which she died, simply from seeing a strange doctor enter the room. Whatever may be the cause which paralyzes the action of the womb we should endeavor, if possible, to discover and remove it. If however it be beyond our reach, the patient's strength must be supported as much as possible, and the simplest means of exciting the contractions tried first; if these fail the more powerful ones must be tried, always preferring the safest. Finally, if all fail, the hand must be introduced into the womb, the child turned, and brought away by the feet; or the forceps must be used if absolutely necessary. RIGIDITY OF THE MOUTH OF THE WOMB, VAGINA AND VULVA.