It is often said that neither heredity nor environment accounts for a man's conduct. And that is true. But it is true, also, that heredity _and_ environment account for every quality in the human "make-up." A pianist, an artist, or a cricketer is "made as well as born," and so is every man. A good batsman is a good batsman for two reasons: (1) He was born with good sight, steady; nerves, and sound sense, all of which he owes to his ancestors. (2) He has been well taught, or has practised well, and this practice, this endeavour to succeed, he owes to his inherited ambition, and to the precept and example of other men. So if a man plays a fiddle well, or steers a ship well, or devotes his life to charity, the excellence is always due to heredity _and_ environment. For the cricketer would never have been a cricketer, nor the violinist a violinist, had he been born in a country where cricket and violin playing were unknown. And, on the other hand, a man bred amongst cricketers or musicians will never excel in music nor in cricket unless he has what is called "a gift"; and the gift is "heredity." NOW, WHAT DO WE MEAN BY "HEREDITY"? Heredity is "descent," or "breed." Heredity, as the word is here used, means those qualities which are handed down from one generation to the next. It means those qualities which a new generation inherits from the generation from whom it descends. It means all that "is bred in the bone." If a man inherits a Grecian nose, a violent temper, well-knit muscles, a love of excitement, or a good ear for music, from his father or mother, that quality or feature is part of his heredity. It is "bred in him." Every quality a child possesses at the moment of birth, _every_ quality of body or of mind, is inherited from his parents and their ancestors. And the whole of those qualities--which _are_ the child--are what we call "heredity." No child brings into the world one single quality of body or mind that has not been handed down to it by its ancestors. And yet no two children are exactly alike, and no child is exactly like any one of its forbears. This difference of children from each other and from the parent stock is called "variation." Hundreds of books and papers have been written about "variation," and to read some of them one might suppose variation to be a very difficult subject. But it is quite simple, and will not give us any trouble at all. Let us see. WHY WE ARE NOT ALL ALIKE The cause of variation can be easily understood. Variation is due to the fact that every child has two parents. If these two parents were exactly alike, and if their ancestors had been all exactly alike, their children would be exactly like each other and like their parents. But the father and mother are of different families, of different natures, and perhaps of different races. And the ancestors of the father and mother--millions in number--were all different from each other in nature and in descent.