Spermatozoön Penetrating the Ovum.
What becomes of all the other spermatozoa? They perish. Only one is needed. But in the ovum that has been impregnated, and which is now called an embryo, a feverish activity commences. First of all it looks for a fixed place of abode. If the ovum happened to be in the uterus when the spermatozoön met and entered it, it remains there. It becomes attached to some spot in the lining of the womb and there it grows and develops, until at the end of nine months it has reached its full growth, and the womb opens and it comes out into the outside world. If the ovum is in the Fallopian tube when the spermatozoön meets it, as is usually the case, it travels down to the uterus, and fixes itself there.
Extra-Uterine Pregnancy. The tube is a bad place for the ovum to grow and develop, because the tube cannot stretch to such an extent as the uterus can, nor can it furnish the embryo such good nourishment as the uterus can. Occasionally, however, it happens that the impregnated ovum remains in the tube and develops there; we then have a case of what we call extra-uterine (outside-of-the-uterus) or tubal pregnancy. Extra-uterine pregnancy is also called ectopic pregnancy, or ectopic gestation. Unless diagnosed early and operated upon, the woman may be in great danger, for after a few weeks or months the tube generally ruptures.
From the moment the spermatozoön has entered the ovum, a process of division or segmentation commences. The ovum, which consists of one cell, divides into two, the two into four, the four into eight, the eight into sixteen, these into thirty-two, these into sixty-four, 128, 256, 512, 1,024, until they can no longer be counted. This mulberry mass of cells arranges itself into two layers, with a cavity in between. And from these layers of cells there develop gradually all organs and tissues, until a fully formed and perfect child is the result. If two ova are impregnated at the same time by two spermatozoa, the result is twins.5
I might mention here that the moment the ovum is impregnated, i.e., joined by a spermatozoön, it is called technically a zygote; it is also called embryo, and this name is applied to it until the age of five or six weeks. Some use the term embryo up to two or three months. After that, until it is born, it is called fetus.
A study of the development of the embryo and the formation of the various organs from one single cell, the ovum, vitalized or fecundated by another single cell, the spermatozoön, is the most wonderful and most fascinating of all studies. But that belongs to the domain of Embryology, which is a separate science.
What we see in the process of fecundation is a foreshadowing of the future man and woman. The ovum has no motion of its own, it is moved along by the wave-like motions of the lining cells of the Fallopian tube, and throughout the entire act it remains passive. The spermatozoön, on the other hand, is in a state of continuous activity from the moment it has been ejaculated by the male until it has reached its goal—the ovum. And as the spermatozoa carry in them the entire impress of the man, and the ova of the woman, they foretell us the fates of the future boy and girl. The woman's rôle throughout life is a passive and the man's an active one. And in choosing a mate the man will always be the active factor or pursuer. So biology seems to tell us. Whether education—using the word in its broadest sense—will effect a radical change in the relation of man and woman remains to be seen. A change putting the man and the woman on a footing of equality would be desirable; but whether biological differences having their roots in the remotest antiquity can be obliterated, is a question the answer of which lies in the distant future. As Geddes and Thomson so well said: The differences [between the sexes] may be exaggerated or lessened, but to obliterate them it would be necessary to have all the evolution over again on a new basis. What was decided among the prehistoric Protozoa cannot be annulled by act of Parliament.
Chapter Ten
PREGNANCY
Period of Pregnancy in Human Female—Physiologic Process of Pregnancy—Growth of Embryo from Moment of Conception—Pregnant Woman Provides Nourishment for Two—Her Excreting Organs Must Work for Two.
From the moment the ovum has been fertilized or fecundated by the spermatozoön, the woman is said to be pregnant (or in French enceinte. This term was used very frequently and is still used by prudes, who seem to consider the word pregnant vulgar and disgraceful). Pregnancy, or the period of gestation, lasts from the moment of conception to the moment that the fetus or child is expelled from the uterus. The period of pregnancy differs very widely in different animals,6 but in the human female it lasts nine calendar months or ten lunar months—from about 274 to 280 days. We usually count 280 days from the first day of the last menstruation. A pregnant woman generally wants to know the day of the expected confinement—for this purpose a table is appended to this chapter. If you know the first day of your last menstruation, you will see at a glance when the confinement may be expected. There may be a difference of a few days—either before or after the expected date—but for practical approximate purposes the tables serve very well.
A simple way is to count back three months and add seven days. For instance, a woman's last menstruation occurred on April 4th; counting back three months gives you January 4th; add seven days and you get January 11th, the probable date of delivery. The first day of the last menstruation was December 30th; counting back three months gives you September 30th; add seven days and you get October 6th, the probable date of delivery. The presence of a short month like February may be disregarded, as the calculation is not absolutely, but only approximately correct.
The period at which the child's movements begin to be felt by the mother is termed Quickening. It usually occurs at the middle of the pregnancy, between the 16th and 18th week.
Pregnancy is a normal physiological process; but every active physiological process is apt to be accompanied by disturbances, and there is certainly no process in the animal body in which greater activity, greater changes, go on than during the process of pregnancy. Just see what occurs in nine months. The uterus, at first the size of a small pear, reaches a size larger than that of the head of a big man; it does not merely stretch, as some think, but it actually grows enormously in size, the muscular walls of a pregnant uterus being many times thicker than those of a non-pregnant one. They have to be or they would not have the strength to expel the child, when the proper time comes. It is to be borne in mind that the child does not slip out by itself; it is the powerful muscular contractions of the uterus that push it out. If the uterus should refuse to work, if its walls were too thin or too weak, the child could not come out, but would have to be taken out with forceps. Still greater changes than in the uterus take place in the child itself. At the moment of conception it is the size of the head of a pin; at the moment of birth it weighs from seven to ten pounds; at the moment of conception it is a minute, undifferentiated mass of protoplasm, just a single fertilized cell; at the moment of birth it consists of millions and millions of cells, which have become differentiated into numerous harmoniously working organs, and different tissues, such as brain and nerve tissue, muscular tissue, connective tissue, bone, cartilage, etc., etc. A truly wonderful process. And in the meantime this child, which is biologically a parasite (though it is not a nice name to call it by) draws its sustenance from the mother's blood, and the mother has to provide nourishment for two. And, besides providing nourishment, her excreting organs, her kidneys, must work for two, because her system has also to get rid of the child's excretions. No wonder that the pregnant woman, particularly under an artificial unhealthy mode of living, is subject to many troubles and disturbances.
DR. ELY'S TABLE FOR