Page:Popular Science Monthly Volume 37.djvu/376

362 qualities are, as we have seen, partly physical—the shape of the skull, the structure of the brain, the color of the skin—and partly psychical, the intellectual and moral faculties. The zoölogical qualities are also partly physical and partly psychical: of the former class, the general structure of the body and the particular structure of organs, as the heart, lungs, glands, etc.; of the latter class, the faculties of intelligence. It appears, therefore, that the zoölogical qualities are the same in kind with the anthropological, and the inference, therefore, is that the law of heredity extends also to them. That is to say, as we proceed, step by step, from the most specific to the most general qualities peculiar to man, and then by the next step pass to those qualities which we possess in common with the highest animals, we find that the last term of the series is the same in kind with the others, and all the reasons that lead us to conclude that the law of heredity extends successively through the first terms of the series lead us to conclude that it extends also to the last.

The fact that not all the anthropological qualities have their zoölogical prototypes does not at all affect the force of the inference. We may allow, for example, that the moral faculties are strictly anthropological; but this does not detract from the evidence that the intellectual faculties came from the zoölogical prototypes, any more than the fact that the Italian people have dark complexions detracts from the evidence that they descended from Caucasian progenitors. In other words, the possession of specific qualities by a class—qualities not received by inheritance—affects in no way the evidence that the general qualities of the class were received by inheritance. We have recognized this principle at each step in the present discussion. For example, we saw that the national characteristics of a people arise from other causes than inheritance, but this did not lead us to conclude that the race characteristics of the same people were not inherited. In fact, every person affords in his own facial features an illustration of this principle. The expression of our countenances, whether intelligent or dull, cheerful or grave, etc., has been determined by the circumstances of our lives—education, etc.; but the anatomical features—color of eyes, shape of nose, etc.—are inherited from our parents.

Our conclusion, therefore, is that the evidences that man has inherited his anthropological qualities apply equally as well to his having inherited his zoölogical qualities.

Below those qualities which man has in common with the higher animals are others which he possesses in common with the lower animals also. These are chiefly anatomical and physiological in character, such as the possession of bodies whose structural units consist of cells, organs which perform the functions of