In the next place, I mention that one abortion paves the way for another, because, setting other circumstances aside, it gives the uterus a tendency to stop its action of gestation at an early period after conception, and therefore it is difficult to make a woman go to the full time, after she has miscarried frequently. We also find that an excessive or indiscriminate use of venery either destroys the power of the organs of generation altogether, making the woman barren, or it disposes to abortion, by enfeebling these organs. Some slight change of structure in part of the uterus, by influencing its actions, may, if it do not prevent conception, interfere with the process of gestation, and produce premature expulsion. If, however, the part affected be very small, and near the os uteri, it is possible for pregnancy to go on to the full time. Indeed, it generally does go on, and the labour, as may be foreseen, will be very tedious; but the operation of cutting the indurated os uteri, which has been proposed, is seldom necessary. I have known one instance, in which a very considerable part of the uterus, I may say almost the whole of it, was found, after delivery, to be extremely hard, and nearly ossified: but this state could not have existed before impregnation took place, for I cannot conceive that so great a proportion of the uterus should have been originally diseased, and yet that conception, and its consequent actions, should take place; but there is no difficulty in supposing, that, during the enlarging of the uterus, the vessels deposited osseous or cartilaginous matter, instead of fibres. In this case, it is evident that the delivery must be instrumental, owing to the deficiency of fibres, and recovery can seldom take place. Often we find this morbid action affect the placenta, instead of the uterus; but this is not dangerous. A general weakness of the system, which must affect the actions of the uterus, in common with those of other organs, is likewise to be considered as giving rise to abortion, though not so frequently as was at one time supposed. The uterus is not only affected by the general conditions of the system, more especially with regard to sensibility, and the state of the blood-vessels; but it likewise sympathizes with the principal organs, and may undergo changes in consequence of alterations in their state.