PREGNANCY AND ITS MANAGEMENT.
The Female Element in Conception.— Every four weeks, as has been stated, in the adult woman, an ovum becomes ripe and is discharged from the ovary. It is caught by the extremity of the fallopian tube and passed down the tube towards the womb. If the changes arising from conception do not occur, the ovum breaks down and disappears. If, however, shortly before it leaves the ovary, or during its descent of the fallopian tube, the ovum is met by the male element, which enters into it and fertilizes it, a set of changes occurs in it which leads to the formation of a new being.
The Male Element in Coneeption.—The material supplied by the male, called the sper matic fluid, consists of a thick whitish fluid, in which the microscope reveals curious bodies, represented in Fig. 208, formed of an oval part, called the head, which is about the of au inch long, and of a tail, the .h of an inch in length. They are called spermatozoa, and they are the essential element supplied by the male for conception. The fluid having been introduced into the female in the act of sexual intercourse, the spermatozoa find their way wards into the womb and on to the fallopian tube, partly by the lashing movements of the tail, and if in their course they meet an ovum, still in fit condition, one or more spermatozoa ing it produce conception.
Among the earliest changes that thereafter occur in the ovum is one by which, from the original single cell, a mass of cells is produced. Fig. 209 shows at 4 ova, magnified. Soon after the entrance of the spermatozoa the ovum divides into two (i of fig.); each of these two then subdivides into two, making four (2 of fig.); each of the four subdivides, so that eight are formed, and the process goes on to sixteen, thirty-two, four, &c., until a mulberry-shaped mass of cells (3) is formed, all derived from the original single cell or ovum. This process is supposed to occupy about eight days, and to occur while yet the ovum is descending the fallopian tube, and about the end of that time it reaches the womb, which has meanwhile been prepared for its reception, and where it is detained till the new being is more fully formed. It is from the The Date of Conception—While concep tion is more likely to result from connection shortly before or within a few days after an "illness," there is really no period at which intercourse may be had and conception not be possible.