Mechanical irritations of the os uteri, or attempts to dilate it prematurely, will also be apt to bring on muscular contraction. At the same time, it is worthy of remark, that the effect of these irritations is generally at first confined to the spot on which they act, a partial affection of the fibres in the immediate vicinity of the os uteri being all that is, for some time, produced; and therefore slight uneasiness at the lower part of the belly, with or without a tendency in the os uteri to move or dilate, whether brought on by irritation at the upper part of the vagina or os uteri, or by affection of the neck, of the bladder, &c.[10] may be often prevented from extending farther, and destroying the action of gestation by rest, anodynes, and having immediate recourse to such means as the nature of the irritation may require for its removal. Tapping the ovum, by which the uterus collapses and its fibres receive a stimulus to action, is another cause by which abortion may be produced; and this is sometimes, with great propriety, done at a particular period, in order to avoid a greater evil. It is now the general opinion, that contraction will unavoidably follow the evacuation of the waters. But we can suppose the action of gestation to be in some cases so strong as not to stop in consequence of this violence, and, if it do not stop, contraction will not take place. I do not, however, mean to say, that all discharges of watery fluid from the uterus, not followed by abortion, are discharges of the liquor amnii, and instances of this failing to produce contraction. On the contrary, I know that most of these are the consequence of morbid action about the os uteri, the glands yielding a serous instead of a gelatinous fluid, and this action may continue for many months. Sometimes the upper range of lacunæ yields water, whilst the under secretes jelly, which confines the water for some hours, until it accumulates, and comes out with a small gush. At other times, in the early period of gestation, it collects in considerable quantity betwixt the lower part of the decidua protrusa, which has not yet reached the cervix uteri and the cervical efflorescence, which becomes a little stronger than usual. There is thus a species of dropsy produced, and the water is sometimes confined until a little before labour comes on; at other times it is discharged sooner, and an oozing continues for many weeks. In all these cases, we may derive some advantage from injecting three or four times a day a strong infusion of galls. The woman ought to use no exertion, as the membranes are apt to give way.