You need not be afraid that I am going to enter upon the much discussed subject of heredity, whether in its physiological or psychological aspects. It is a favourite subject just now, and the most curious facts have been brought together of late to illustrate the working of what is called heredity. But the more we know of these facts, the less we seem able to comprehend the underlying principle. Inheritance is one of those numerous words which by their very simplicity and clearness are so apt to darken our counsel. If a father has blue eyes and the son has blue eyes, what can be clearer than that he inherited them? If the father stammers and the son stammers, who can doubt but that it came by inheritance? If the father is a musician and the son a musician, we say very glibly that the talent was inherited. But what does _inherited_ mean? In no case does it mean what _inherited_ usually means--something external, like money, collected by a father, and, after his death, secured by law to his son. Whatever else inherited may mean, it does not mean that. But unfortunately the word is there, it seems almost pedantic to challenge its meaning, and people are always grateful if an easy word saves them the trouble of hard thought. Another apparent advantage of the theory of heredity is that it never fails. If the son has blue, and the father black, eyes, all is right again, for either the mother, or the grandmother, or some historic or prehistoric ancestor, may have had blue eyes, and atavism, we know, will assert itself after hundreds and thousands of years. Do not suppose that I deny the broad facts of what is called by the name of heredity. What I deny is that the name of heredity offers any scientific solution of a most difficult problem. It is a name, a metaphor, quite as bad as the old metaphor of _innate ideas_; for there is hardly a single point of similarity between the process by which a son may share the black eyes, the stammering, or the musical talent of his father, and that by which, after his father's death, the law secures to the son the possession of the pounds, shillings, and pence which his father held in the Funds.