It sometimes happens, that instead of the impregnated ovum passing into the womb, it is either retained in the ovarium,^[463] or it stops in the fallopian tube, or it misses the tube and falls amongst the bowels. Of these, the tubal is by far more frequent than the ventral conception. We learn from the numerous cases which are recorded of extra-uterine pregnancy, that it may terminate in several different ways; in some cases sudden death occurs from hemorrhage;^[464] in others, the unfortunate woman survives for a long period; and it has occurred that the foetus has been converted into a substance somewhat analogous to the gras de cimetiÈres,^[465] in which case very little inconvenience is felt beyond that which must attend the tumour of the belly for so many years. Nature, however, more generally institutes a process to get rid of the extraneous body; the sac adheres to the peritoneum or intestines, and, after an uncertain period, varying from a few weeks to several years, it either opens externally, or communicates with the abdominal viscera, and highly offensive matter, together with putrid flesh, bones, and coaguli, are discharged through the abdominal integuments, or by the rectum,^[466] vagina, or bladder.^[467]

The most extraordinary circumstance in the history of these conceptions is the sympathetic enlargement of the uterus, and even in some cases, the formation of the Membrana Decidua.^[468] Riolanus^[469] was the first person who noticed these conceptions. Vesalius observed a tubal conception at Paris in 1669; the foetus was four months old, and the tube was so enlarged, that he mistook it for a second uterus, and actually published an account of it, under the title of “Demonstration d’une double Matrice.” De Graaf, and afterwards a learned German by the name of Elshotius commented upon this case in a tract entitled “De Conceptione Tubaria, qua humani foetus extra uteri cavitatem in tubis quandoque concipiuntur,” in which is given the figure of the two supposed uteri, and the foetus in the distended tube. In the Journal des SÇavans, A. D. 1678, a case is recorded of a woman at Paris who carried an extra-uterine foetus in the omentum for twenty years; and in the Philosophical Transactions there is an account of a foetus of this description, by Dr. Steigerthal, that remained in the body of the mother for upwards of forty years. In the present state of our physiological knowledge it is impossible to offer any explanation of the cause of these anomalies in the law of Nature, but we recommend to the attention of the student a paper by Dr. Blundell, on the Physiology of Generation, to which we have before taken occasion to allude^[470] in terms of high commendation.