In by far the majority of cases which have been recorded, the pains have after a time been sufficient to dilate the os uteri. Dr. Campbell has described two of these cases, where no os uteri could be traced for some time after the commencement of labour: both were first pregnancies: in the former, uterine action continued about twelve hours before the os uteri could be distinguished, when it felt like a minute cicatrix; the other patient had regular pains for two nights and a day before the os uteri could be perceived, and she suffered so much as to require three persons to keep her in bed; both these patients were largely bled, gave birth to living children, and had a good recovery. We may suspect that the protraction of labour arises from agglutinated os uteri, when at an early period of it we can discover no vestige of the opening in the globular mass formed by the inferior segment of the uterus, which is forced down deeply into the pelvis, or at any rate, where we can only detect a small fold or fossa, or merely a concavity, at the bottom of which, is a slight indentation, and which is usually a considerable distance from the median line of the pelvis. The pains come on regularly and powerfully; the lower segment of the uterus is pushed deeper into the cavity of the pelvis, even to its outlet, and becomes so tense as to threaten rupture; at the same time it becomes so thin, that a practitioner who sees such a case for the first time would be induced to suppose the head was presenting merely covered by the membranes. After a time, by the increasing severity of the pains, the os uteri at length opens, or it becomes necessary that this should be effected by art: when once this is attained, the os uteri goes on to dilate, and the labour proceeds naturally, unless the patient is too much exhausted by the severity of her labour. Although the obstacle in some cases is capable of resisting the most powerful efforts of the uterus, a moderate degree of pressure against it whilst in a state of strong distention, either by the tip of the finger, or a female catheter, is quite sufficient to overcome it; little or no pain is produced, and the appearance of a slight discharge of blood will show that the structure has given way. Two interesting cases of this kind have been described by the late W. J. Schmitt, of Vienna, under the title of two cases of closed os uteri which had resisted the efforts of labour, and where it was easily dilated by means of the finger.[127]