But it appears that the materialist maintains that the law of heredity is fixed and unchangeable, at all events it is proof against secondary causes. For example, no sort of treatment, nor any kind nor quantity of food will make a mouse grow to the size of an elephant nor any larger than his ancestors were. Food and environment are “secondary causes;” but they have no power to change the form nor the size of the animal body. Since all normal adult individuals of each species of animals, all over the earth, and in every age, have substantially the same form and size; and since each individual is built up, anew, of new cells (or atoms) by new forces and motions, we are compelled to assume that the same psychic force or agency determines the number of cells which shall go into each normal body, and the manner in which these cells shall be grouped together. In brief, the same supernatural psychic and creative force, always, determines the form and size of each animal, all over the earth. 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.)