We may, therefore, consider that a genuine uterine contraction consists of certain phenomena which occur in the following order: first, the os uteri grows tight, and the presenting part rises somewhat from it; then the rest of the uterus, especially the fundus, becoming hard, the patient has a sensation of pain, and the presenting part of the child advances. The period of time necessary for all these changes varies not only in different individuals, but in the same individual in different labours, and in different stages of the same labour. "The more completely the os uteri is opposite the fundus, and the more the axis of the uterus corresponds with that of the pelvis, the sooner are the pains, _cæteris paribus_, capable of dilating the os uteri." (_Wigand_, vol. ii. p. 273.) The cushiony state of the vagina and os uteri, and the free secretion of thick albuminous mucus from these parts, as already mentioned, will be of great importance in ensuring their easy dilatation. Where this secretion is either absent, or very scanty, the passages become dry, hot, and tender, from no relief being afforded to the congested vessels by its effusion; and _vice versâ_, where there is a febrile state of the circulation and considerable topical excitement, the secretion is sparing, or, perhaps, stops entirely. This state may arise from a variety of causes, such as from general plethora, too warm clothing, bad ventilation, derangement and irritation of the primæ viæ, and abuse of spirituous and other stimulating liquors: it may arise from constipation, or may be induced by rough and too frequent examination. The patient becomes flushed, excited, and feverish, with a hot skin, dry tongue, thirst, and headach; the uterine contractions become irregular, they produce much suffering, and but very little advance in the progress of the labour; the passages are in a state of inflammation, and more especially the os uteri, which is much swollen and excessively tender. The process of labour is completely interrupted, and can only be restored to a healthy condition by bleeding, warm bath, laxatives, and enemata.