One hears of the physiological law thus violated, whenever the question of a marriage between cousins is mooted. The tendency of such a marriage, we are always told, is to perpetuate and accentuate typical characteristics and weaknesses, both physical and moral. A single marriage between cousins may produce no perceptible evil result; and one can cite cases in which it appears to have produced remarkably brilliant results.[1] But a series of such marriages, continued through generation after generation, invariably and inevitably tells. The family, or the community, in which such unions are the rule, loses vigour and develops peculiarities—a special, readily recognisable, physiognomy, and an unstable mental equilibrium. The transmitted eccentricities—more particularly the mental eccentricities—may skip a generation or leave an individual exempt; but they are always lurking in the background—always to be expected to reappear. [Footnote 1: Darwin married his first cousin, and all his sons were men of remarkable ability.] It has been so, and is so, according to Drs. Rubbrecht and Galippe, with the Habsburgs. We have all heard of the “Habsburg jaw”; and Dr. Rubbrecht traces it to its mediæval source, and, standing before a long row of family portraits, carefully and scientifically depicts the Habsburg face:— “In addition to the underhung lower jaw and the large lower lip, the Habsburg physiognomy presents the following characteristic features: excessive length, and, sometimes, excessive size of the nose; ‘exorbitism,’ more or less pronounced, with a forehead often of considerable height. One would say that the head, squeezed in by lateral pressure, had undergone a concomitant vertical allongation, and had been stretched, and pulled up and down at the same time. According to Dr. Galippe, the lateral flattening of the skull is the fundamental characteristic, and all the other abnormalities follow from it.” That is what Dr. Rubbrecht makes of the portraits. He generalises only as a student of physiognomy, and does not discuss mental and moral issues, or presume to predict the future. Dr. Galippe is more outspoken:— “The Habsburgs” (he writes), “having, by their intermarriages, developed a degenerate taint, and having transmitted it, either separately or in conjunction with other taints, both physical and psychical, to the families matrimonially allied with them, have brought into existence a specific type of human animal, by the same means which the breeders of dogs and horses employ for the creation of a new sub-species.” As for the general consequences of such in-breeding, he continues:— “Even those aristocratic families which present no original mark of degeneracy disappear quickly. It follows, _a fortiori_, that those families which, possessing such characteristics, perpetuate them by contracting marriages within the degrees of consanguinity, are doomed to a still more speedy extinction.”