1).

The fateful meeting of the sperm and the ovum takes place usually in
the upper end of one of the fallopian tubes. It is a wonderful
occasion. The wide-awake, vibrating lifelike sperm plunges head first
and bodily into the ovum. The tail, which has propelled this bundle of
life through the many wanderings of its long and perilous journey, now
no longer needed, drops off and is lost and forgotten. This union of
the male and female sex cells is called "fertilization." There
immediately follows the most complete blending of the two germ
cells--one from the father and one from the mother--each with its
peculiar individual, family, racial, and national characteristics.
Here the combined determiners determine the color of the eyes, the
characteristics of the hair, the texture of the skin, its color, the
size of the body, the stability of the nervous system, the size of the
brain, etc., while the suppressors do a similar work in the
modification of this or that family or racial characteristic.

THE FIRST WEEKS OF LIFE

The fertilized ovum remains in the tube for about one week, when it
slowly makes its way down into the uterus, all the while rapidly
undergoing segmentation or division. It does not grow much in size
during this first week, but divides and subdivides first, into two
parts, then four, then eight, then sixteen and so on, until we have a
peculiar little body made up of many equally divided parts, and known
as the "Mulberry Mass" (Fig. 1). The blending of the sperm and ovum
has been perfect, the division of the original body multitudinous.

[Illustration:
Sperm and Ovum Cell Division

Fetus at Six Weeks Fetus at Three Months

Fig. 1. Steps in Early Development]

While this division of the united sex cells is progressing, a
wonderful change is also taking place in the inside lining of the
uterus. Instead of the usual thin lining, it has greatly thickened and
has become highly sensitized, and as the ovum enters the uterus from
the fallopian tube, this sensitized lining catches it and holds it in
its folds--actually covers it with itself--holding the precious mass
much as the cocoon, you have so often seen fastened to the side of a
plant or leaf, holds its treasure of life.

Just as soon as the new uterine home is found the baby heart begins to
make its appearance, as also do many other rudimentary parts. By the
end of the third week, our round mass has flattened and curved and
elongated