The lesson which this law teaches might be stated in five words, to wit: _Breed only from the best_--but the teaching may be more impressive, and will more likely be heeded, if we understand the extent and scope of the law. Facts in abundance show the hereditary tendency of physical, mental and moral qualities in men, and very few would hesitate to admit that the external form and general characteristics of parents descend to children in both the human and brute races; but not all are aware that this law reaches to such minute particulars as facts show to be the case. We see hereditary transmission of a peculiar type upon an extensive scale, in some of the distinct races, the Jews, and the Gypsies, for example. Although exposed for centuries to the modifying influences of diverse climates, to association with peoples of widely differing customs and habits, they never merge their peculiarities in those of any people with whom they dwell, but continue distinct. They retain the same features, the same figures, the same manners, customs and habits. The Jew in Poland, in Austria, in London, or in New York, is the same; and the money-changers of the Temple at Jerusalem in the time of our Lord may be seen to-day on change in any of the larger marts of trade. How is this? Just because the Jew is a "thorough-bred." There is with him no intermarriage with the Gentile--no crossing, no mingling of his organization with that of another. When this ensues "permanence of race" will cease and give place to variations of any or of all sorts. Some families are remarkable during long periods for tall and handsome figures and striking regularity of features, while in others a less perfect form, or some peculiar deformity reappears with equal constancy. A family in Yorkshire is known for several generations to have been furnished with six fingers and toes. A family possessing the same peculiarity resides in the valley of the Kennebec, and the same has reappeared in one or more other families connected with it by marriage. The thick upper lip of the imperial house of Austria, introduced by the marriage of the Emperor Maximillian with Mary of Burgundy, has been a marked feature in that family for hundreds of years, and is, visible in their descendants to this day. Equally noticeable is the "Bourbon nose" in the former reigning family of France. All the Barons de Vessins had a peculiar mark between their shoulders, and it is said that by means of it a posthumous son of a late Baron de Vessins was discovered in a London shoemaker's apprentice. Haller cites the case of a family where an external tumor was transmitted from father to son which always swelled when the atmosphere was moist.