Sec. 25. Distribution and Grouping of Cells in the Embryo Body
As already stated, every man and woman begins life as a germ-cell or fertilized ovum. This cell grows and divides into two daughter-cells; these into four, eight, sixteen, thirty-two, and so on. At first these daughter-cells are so distributed and grouped as to form a solid ball called “the morula;” next they take the form of a hollow ball, called “the blastula” with a single layer or sheet of cells and a fluid in the center; next a group of cells with two layers, called “the gastrula;” then they are so distributed or grouped as to form two germ-layers or sheets of cells, then into three layers, then into four. At this point a portion of the cells is so grouped as to begin the formation of the spinal cord and brain; and in course of time, other cells are so distributed and grouped as to form the bones, muscles, nerves, arteries, veins, heart, lungs, stomach, liver, kidneys, intestines, arms, hands, legs, feet and other organs and parts of the body.
The form of any animal body and each organ and part of such a body, depends upon the manner in which its cells are distributed and grouped. Thus, the form of the whale, elephant, giraffe, camel, lion, tiger, hippopotamus, alligator, python, horse, cow, eagle and humming-bird, is produced by the distribution of the cells or atoms in their bodies. If a man has a very large head, a long nose or big foot we are compelled to infer that these peculiarities are the result of depositing an unusual number of cells (“organic bricks”) in these parts of his body.
Sir Isaac Newton states his first law of motion in the words following:
“Everybody continues in its state of rest, or of uniform motion in a straight line, except in so far as it is compelled, by force, to change that state.”—(Encyc. Brit. (9 ed.) 15, p. 676.)
For example, if one should lay a stone on the ground it would remain there forever, unless moved by some sort of force. It would be absurd to suppose that the stone could, automatically, move itself.
There is no such thing as making any thing out of nothing. Every thing is made of some other thing. The body of the horse is made of corn, hay and other vegetable and mineral substances. So the human body is made of bread, meat and other food-stuffs, eaten by the mother before birth and by the individual, himself, after birth. The germ-cell is deposited in the womb of its mother. It cannot develop nor grow, unless it receive nourishment from her body. She eats bread, meat and other things, these are converted into blood, and a portion of it is carried, by the force of her heart and arteries, to the germ-cell; it absorbs and assimilates a portion of the blood; produces cells; and these are so distributed and grouped as to form the embryo body with all its organs and parts.
It is obvious that the father has nothing to do with the circulation of the mother’s blood, which conveys nourishment to the embryo; it is equally clear that she has no conscious part in the circulation of her own blood, and that she has no power nor control over the development nor the growth of the embryo, except such as she may exert indirectly by the food which she eats.
The embryo begins life as a germ-cell. Atoms of building material must be conveyed, by the blood of the mother, to this cell, otherwise, it cannot develop nor grow. As new cells are produced, they are so distributed and grouped as to form the several organs and parts of the embryo body; or it may be said that new cells are produced and added to older cells, at such points as to build up the embryo organs and parts. For example, arm-buds and leg-buds appear on the surface of the trunk, as slight swellings or projections; new cells are added to these buds; they grow, in length, by the addition of cells at the distal (outer) ends, until they have attained the proper length, terminating in the fingers and toes. So the arms and legs grow to some extent in diameter by the addition of new cells; but the number of cells, which go to extend the length of the arms and legs, greatly exceeds the number which go to increase the diameter.