At the time of a fruitful connection, which can only occur, it must be remembered, when the ovum is ripe, the male principle is carried into the Womb, (B, Plates I. and III.) and is then supposed, by some, to meet with the ovum which has descended down the Fallopian Tube (f, Plates I. and III.) from the Ovary, so that the union of the two takes place, according to this view, either in the Fallopian Tube or in the Womb. Others, however, suppose that the ovum does not leave the Ovary before conception, but that the male principle passes down the Fallopian Tube and meets it there, and that it is several days after before it reaches the Womb. There are many facts and arguments brought forward in support of each view, all of which will be set forth in my forthcoming work on the reproductive functions. All that is known for certain is, that the two principles must unite in one place or the other, and that the ovum must pass down the Tube into the Womb, either before impregnation, or after.
The union of the two principles in the Womb appears so likely an event that it is scarcely possible to avoid thinking that it really does then take place, but at the same time there are very strong reasons for adopting the opinion that it takes place in the Ovary. Among others may be mentioned the phenomenon of extra uterine conception, which will be more fully alluded to in another place. In these cases the fœtus is found outside of the Womb, in the Tube, or the Ovary, or even in the Abdomen, among the intestines. Such an occurrence seems to render it almost certain that the ovum must have been fecundated in the Ovary, because we cannot well conceive, if it were not so, how it could reach the outside of the Womb. This difficulty is not, however, regarded as insuperable, by the advocates of the opposite theory. Possibly conception may occur in both ways.
There are many causes which prevent conception, or, in other words, which produce barrenness and sterility. These various causes cannot be all explained, except in connection with a full explanation of the process of reproduction, and of the nature of many female diseases. In my work on "The Diseases of Woman," I have given a chapter on this subject, and have also referred to the present work as one in which it would be more fully treated. This reference, however, was made in mistake; the subject is not needed here, but will be in the other work, on the reproductive functions in which it will be discussed at length.
CHAPTER IV.
FŒTAL DEVELOPMENT.
The last Chapter brought us up to the point of conception, or the first commencement of the new being. The next step is to exhibit its various stages of development, and to show how it is nourished and maintained in its proper position. This is requisite in order to understand the origin of many diseases and accidents which occur during gestation, and also to explain the various signs by which it is determined whether a female is pregnant or not.
FŒTAL DEVELOPMENT.
The development of a perfectly formed human being from the egg in which it originates, is one of the most astonishing phenomena that can come under our observation, and is eminently deserving the study of every rational being. The present explanation of it must necessarily be brief, being merely intended to make the main subject more clear.
It has already been remarked that it is uncertain whether the ovum is impregnated before it is brought into the Uterus, or after it arrives there; but be that as it may, nothing has yet been discovered in the Womb till several days after conception. Some physiologists tell us that the rudiment of the new being may be found there about the sixth day; but others again assure us that it cannot be found before the twelfth, at which period our explanation of its development will commence.