Page:Popular Science Monthly Volume 12.djvu/332

318 the light, or partly sanguine group, to active inflammations, a potent factor in causing this deficient size of the chest is inflammation, mainly pleurisy and pneumonia, and, as a not uncommon result, a collapse of one, or both, of the chest-walls. This theory is the only one that offers a reasonable explanation of a very remarkable statistical result. The increased ratio in both groups, but notably in the light, of defects or deformities of the feet rather than of the hands, while having no relation to the difference of temperament, shows the careful way in which Nature protects the natural weapons of human beings—the hands. It confirms, in a broad way, what has probably been noticed by the observant reader, that deformities of the lower are more frequent than those of the upper extremities.

These few figures, taken from Dr. Baxter's vast collection of statistics, if not demonstrating anything positively, have at least the merit of not proving too much—a common fault of figures, if we are to believe the anti-statisticians. They are important, however, in showing the direction in which the study of temperaments may be pushed in order to give practical results. Social reformers, so called, human-science men, and less respectable students under various names, have used temperaments as their physiological basis for widely different theories. To one who is content with marriage as established by law, society, and religion, it is a suspicious circumstance that this is the social relation that has sustained the most determined assaults. The physiological attacks have been made in the interests of marriage-reform, "natural marriage," and of no marriage at all. While there is very strong evidence showing that intermarriage between relations tends to the deterioration of the offspring, there are hardly any facts showing that the matrimonial union of healthy persons of like temperaments has the same effect. It is true that social theorists assert the contrary, but they do so without considering that the intermarriage of kin, from which they draw their chief arguments, is surrounded by conditions that cannot exist in the intermarriage of like temperaments. That there are deep-lying physiological reasons against the union of relations, we need go no further than the oft-quoted fact of the sure impairment of the stock of domestic animals from inbreeding, to establish. Whatever the source of this gradual impairment may be, it is wanting in the marriage of those who are allied only by similarity of temperament. In the absence of conditions that are necessary to render the arguments drawn from analogy valid, the advocates of the theory of physiological incompatibility are obliged to fall back upon facts having a direct bearing, and they have in this field, as yet, reaped no harvest. There is, however, in the human family a sort of natural selection existing, that renders a marriage between parties of like temperament not an ordinary occurrence. Both Dr. Ryan and Mr. Walker, in their works on marriage, refer to