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 fœtus 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 fœtus extra uteri cavitatem in tubis quandoque concipiuntur_,” in which is given the figure of the two supposed _uteri_, and the fœtus 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_ fœtus in the omentum for twenty years; and in the _Philosophical Transactions_ there is an account of a fœtus 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. OF HERMAPHRODITES. The term _Hermaphrodite_[471] signifies an animal in which there exists a mixture of the male and female organs, and which is therefore capable of begetting or conceiving. There can be no doubt but that some of the lower orders of animals[472] are, in the strict sense of the term, Hermaphrodites; but it is now universally admitted that, in the human species, no such phenomenon ever existed; indeed, if we only consider the osteology of the pelvis, to the bones of which the organs of generation are connected, it is impossible to imagine how the complete parts of the male and female could be placed distinct from each other; nor is there upon record a single case which can be considered authentic;[473] numerous are the instances of preternatural structure, which gives the appearance of a double sex, and it is on the nature of such monstrous productions, that the medical man is frequently called upon to decide. _Baron Haller_ has industriously collected in one point of view, the histories of reputed hermaphrodites, from almost every author that has preceded him; and from this memoir,[474] and the interesting paper by _Sir E. Home_, entitled “An account of the Dissection of an Hermaphrodite Dog, to which are prefixed some observations on Hermaphrodites in general,”[475] we acknowledge ourselves principally indebted for the following remarks.