so because these are hereditary. The law is constant. Within
certain limits progeny always and every where resemble their parents.
If this were not so, there would be no constancy of species, and a
horse might beget a calf or a sow have a litter of puppies, which is
never the case,--for in all time we find repeated in the offspring the
structure, the instincts and all the general characteristics of the
parents, and never those of another species. Such is the law of nature
and hence the axiom that "like produces like." But while experience
teaches the constancy of hereditary transmission, it teaches just as
plainly that the constancy is not absolute and perfect, and this
introduces us to another law, viz: that of variation, which will be
considered by and by; our present concern is to ascertain what we can
of the law of similarity.

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