MODE OF ASCERTAINING THE PRESENTATION AND POSITION. _The Presentation._--Although in general it is not possible to ascertain with certainty, what part of the fœtus presents to the mouth of the Womb, until labor commences, yet a tolerable judgment can frequently be formed before. In head presentations, on performing ballotment, the head is felt, like a firm round tumor, occupying all the space which the finger can reach, very differently from any other part. The peculiar cramps in the female's lower limbs, and frequent inclination to urinate, mentioned in the signs of labor, are also strong indications of this presentation, being seldom experienced in any other. When the labor has actually commenced there can be but little uncertainty in these cases, for, immediately the mouth of the Womb is sufficiently open, the finger can be introduced, and the head felt like a smooth, round, and elastic bony tumor, not likely to be mistaken for anything else, if ordinary care be taken. After the waters have escaped, it can of course be felt still more distinctly. If even an inexperienced person bears in mind the _shape_ of the head, and reflects how it must _fill up_ the passage, and how it must feel, from being composed of separated thin bony plates, lying on a soft yielding substance like the brain, he can scarcely fail to recognize it. The sensation is very much like that of pressing a piece of firm card board on an inflated bladder, which forms a tolerable representative of the fœtal head. Sometimes there is a difficulty from a great quantity of water being intruded between the membranes and the head, which somewhat obscures the touch, but this only necessitates greater care. The water however, may be in such quantity as to entirely prevent the touch, in which case nothing can be done till the membranes break; the presentation can then be ascertained with certainty, and it will be quite early enough to render assistance, if it should be an unfavorable one. I have known some inexperienced persons mistake the bag of water itself for the head, and commit great errors in consequence. The Face can seldom be mistaken, because the nose, or mouth, may be felt; and, by passing the finger up the side of the head, the ears also. The trunk is in general easy of recognition. Nearly always the right or left shoulder occupies the passage, or is near to it, so that the finger may be readily passed under the arm pit. The shoulder joints, the ribs, or the shoulder blade bone, all feel very different to the head, and are not likely to be taken for it. In presentations of the lower extremities there is still less danger of error. If the feet, or knees, occupy the passage, they can scarcely be mistaken. The breech is certainly something like the head in its form, but feels different, and is divided down the middle by the indentation between the two cheeks, along which the finger can be passed till it enters between the limbs.