The first stage terminates with the full dilatation of the os uteri; the rupture of the membranes is a change which is necessarily more or less uncertain, as to the precise period of labour at which it takes place. Thus, in primiparæ, it frequently occurs before the first stage is completed; whereas in other cases the membranes sometimes do not give way until the head approaches or has even passed through the os externum; generally speaking, however, they burst at this period of the labour, and usually effect a remarkable change in the whole process. The pains are now of longer duration and more powerful, the intervals between them are shorter, and yet, although the suffering is actually more severe, it is more tolerable to the patient than that of the first stage. During the first stage they are chiefly confined to one spot in the loins; and as they must necessarily continue for some hours without any distinct evidence of the labour being advanced by them, the patient feels discouraged and gets a little impatient at the endurance of so much apparently useless suffering: but as soon as the gush of liquor amnii takes place, she feels that a great alteration has been produced; the abdomen becomes smaller: the pains assume a very different character, and every thing combines to assure her that she has made progress, and encourages her to patience and resolution. _Description of second stage._ The os uteri has now disappeared entirely, so that the vagina and uterus form one continuous canal, and is thus admirably adapted for the easy passage of the head: the anterior lip, however, dilates much more slowly than the other parts of it, and this is especially the case in primiparæ, for, being pressed between the head and pelvis it becomes oedematous, and swells to a considerable size: if the pains be strong, it is pushed down more or less before the head, and may be frequently felt beneath the symphysis pubis, and occasionally it is detruded so far as to be visible between the labia. According to Wigand, the swelling of the anterior lip sometimes attains such a size as makes it liable to be mistaken for the bladder of the membranes (_op. cit._ vol. ii. p. 308;) it seldom produces much obstacle to the advance of the head, and with a little patience gradually disappears of itself. All attempts to push it up above the head are objectionable, because, in the first place, the finger cannot reach sufficiently high to effect this object, and therefore the swelling descends again to its former situation; and, secondly, the efforts to push it up only tend to inflame it and increase the swelling. Those who imagine that they can push up the anterior lip of the os uteri above the head deceive themselves; and even if they do succeed, it merely shows that had they let it alone, it would have gone up very shortly of itself.