It will be well to elucidate somewhat the principles thus summarily stated. First, then, as to variation. The offspring is never exactly like its parents, and no two creatures are ever quite alike. The stems, the leaves, the blossoms of the plants of any species, the size and contour of their fruits, vary greatly. No two blades of grass, or ears of corn, or grains of wheat are alike. Every tree has an individuality of form. The young of dogs, cattle, horses, sheep, of fowls and birds, invariably differ from their parents in size and form, in coloring and character. [Illustration: FIG. 42.—THE BRAINS OF ANTHROPOID APES AND MEN. G-Gibbon. H-Chimpanzee. I-Orang. K-Gorilla. L-Bushman. M-Teuton. From Haeckel’s “Evolution of Man.”] So, too, in a large assemblage of people, you will see noses and ears of numerous shapes and sizes, eyes displaying a variety of coloration and expressiveness; you will observe that some foreheads are low and others high, some heads flat and others pointed, some round and others square; some men have long arms and legs, some the reverse; some have long bodies and short limbs, some the opposite; some have one ear, or shoulder, or hip, higher than the other, or are otherwise disproportioned. Moreover, great differences may be observed in the features of almost any family. The black haired mother has red haired daughters; the father’s features are bequeathed to his sons except, perhaps, for the eyes of one or the nose of another. Variation is a basic law of life. Secondly, as to the multiplication of creatures beyond the power of Nature to sustain them. Darwin, in the “Origin of Species” says: “There is no exception to the rule that every organic being naturally increases at so high a rate, that, if not destroyed, the earth would soon be covered by the progeny of a single pair. Even slow-breeding man has doubled in twenty-five years, and at this rate, in less than a thousand years, there would literally not be standing-room for his progeny.” On the fertility of the elephant, Darwin remarks: “The elephant is reckoned the slowest breeder of all known animals, and I have taken some pains to estimate its probable minimum rate of natural increase; it will be safest to assume that it begins breeding when thirty years old, and goes on breeding till ninety years old, bringing forth six young in the interval, and surviving till one hundred years old; if this be true, after a period of from 740 to 750 years there would be nearly nineteen million elephants alive descended from the first pair.”