NATURAL LABOR. The uterine functions are characterized by periodicity. If an abortion occurs that is not the result of an accident, it is generally at what would have been, but for conception, a monthly period, and even injuries are more likely to produce their bad effects at that particular time. So the normal period for parturition corresponds to a menstrual period, and generally labor may be looked for at about the tenth period after the last appearance of the catamenia. We can hardly tell why it so uniformly happens at that particular time; the process is analagous to the falling of ripe fruit—it drops because the fruit is fully matured. It is not in accordance with the plan of this work to dwell at all upon any other than what is called natural labor, but I shall include in this class all such as are terminated by the natural powers, whether they be head, face, breach, or foot presentations. By PRESENTATION, I mean that part that presents itself at the brim of the pelvis, so that the accoucheur’s finger impinges upon it as the end is passed into the center of the os uteri. The DIAGNOSIS of the different presentations is made by the touch. The head may be known by the hardness and roundness, and more certainly by the fontanelles and sutures; the breach by its general softness, and by the tuberosity of the haunch bone; by the cleft between the buttocks, the scrotum or the vulva, and the anus; the knee by the hardness and roundness of the bone; the foot by its form, its being at right angles with the leg, the nearly equal length of the toes, the narrow heel, etc.; and the face by the inequalities of the presenting part. (These inequalities cannot at first be felt; upon touching it we first perhaps detect the brow, then, as labor progresses, we may feel the nose, mouth, etc.) The head presents in about 98 cases out of 100. PHYSIOLOGICAL PHENOMENA OF LABOR. According to the division made by standard authors on parturition, its first stage extends from the beginning of labor to the complete dilatation of the os uteri; the second terminates by the birth of the child, and the third by the expulsion of the placenta. During the last two or three weeks of the term, the uterus sinks lower in the pelvis, and seems to spread out laterally; the lungs and stomach are not so much compressed, and respiration and digestion, if difficult, become more easy, and often the patient becomes more cheerful and active. The precursory symptoms of labor vary in intensity in different women; but it may be observed pretty generally that there is more activity and disposition to movement for one day preceding the real labor. But during the last few days of the gestation there are contractions of the uterus, which, though short and distant, and not attended with much pain, are effective in dilating the cervix, and preparing for the subsequent labors.