2. =Uterine and extra-uterine pregnancy running concurrently to term.= (Compound pregnancy.) This may be described as the most dangerous combination to which child-bearing women are liable. In order to show what a disastrous conjunction it is to women with two ‘quick’ children--one intra- and the other extra-uterine--I have arranged some recorded cases in the table on p. 35. Fortunately this form of compound pregnancy is rare, but a rarer combination has been recorded by Menge, in which the extra-uterine fœtus occupied the ovary and ran nearly to term. When the woman came into labour, the ovarian pregnancy was regarded as an obstructing tumour, and preparations were made for performing cœliotomy. The intra-uterine child was born in the meantime. When the supposed tumour was extracted, to the surprise of all it contained a living fœtus. The mother and both children survived. 3. =Uterine pregnancy complicated with a sequestered extra-uterine fœtus.= This is a very rare condition, but some cases have been very carefully recorded (Leopold, Stonham, Worrall). The physical signs are those of a pelvic tumour incarcerated by a gravid uterus. The nature of the swelling may be sometimes accurately inferred before operation, as in Worrall’s remarkable case. The sequestered fœtus should be removed by cœliotomy. After the death of the fœtus the operative treatment of extra-uterine gestation is, as a rule, a simple proceeding, the fœtus and placenta can be easily and safely removed. We have no certain means of deciding when an extra-uterine fœtus is dead, nor do we know exactly how long after the death of the fœtus the placental circulation ceases, but we do know that in course of time, if the fœtus is retained, the placenta disappears, because in cases where the fœtus is in the condition known as lithopædion there is usually no placenta. When a retained extra-uterine fœtus is wholly or partially converted into adipocere, the tissues have a strong tendency to adhere to the walls of the sac. This is especially marked in connexion with the hairy scalp. Although a sequestered extra-uterine fœtus is uncommon, yet a surgeon may stumble on one when he least expects it: these bodies may remain undisturbed in the pelvis many years, even fifty, and be only discovered in the post-mortem room, but they are always liable to be infected from the adjacent bowel or bladder; then suppuration is inevitable. In some instances the pus makes its escape at the umbilicus, and as the sinus persists the surgeon explores it, and, on laying it open, is surprised when he extracts the fœtus, sometimes entire.