=Twin brothers.=--I once met twin brothers sixty-seven years old. They had been lost to each other for fourteen years. They still resembled each other, dressed alike, wore their beards and hair alike, talked and laughed alike. Sixty-seven years had not greatly modified their physical and mental resemblance. Twin children usually inherit similar perfections or imperfections. This I have noticed for a number of years. Where I am now writing is a club-footed, rheumatic boy. His twin brother is feeble-minded. In an adjoining state a few days ago I studied a young man who was helpless from his arms down. His twin sister was helpless at birth and died in childhood. These examples indicate that the before-birth influences being the same, were the causes of these defects in the offspring. =An objection answered.=--A man said to me, “I don’t believe in heredity.” I asked him why he did not. He replied, “I know of a drunken father who had four sons; two were dissipated from their youth and two were ‘teetotalers.’ If the father had had anything to do with this, all would have been drunkards.” My reply was, “The father through the laws of heredity may have transmitted to two of his boys tendencies toward drunkenness and to the other two, tendencies toward sobriety. In the case of the first two, the father might have, in his mental and moral natures, favored intemperance, longed for alcohol, or been on a drunken debauch at the initial of their lives. With reference to the last two, the father might have temporarily reformed, mentally and morally, he might have been strongly opposed to the use of strong drink at the initial of their lives. “Again the mother might have had very light convictions on temperance prior to the birth of the first two and very strong mental and moral opposition prior to the birth of the last two. Again something in the form of environment may have led the last two to overcome their inherited tendencies toward drink.” =Materialistic theory fails.=--Materialistic philosophers admit that heredity tends to reproduce the likeness of the parents in the child. They try to explain this on a purely physical basis. Prof. Huxley, Mr. Spencer and the more modern Weismann, while they have each coined some new technical terms with which to convey their materialistic ideas, suppose that each procreative cell, masculine and feminine, contains a representative material something from every atom of the respective body from which it was formed. In this way the child has a body with marked resemblance to its parents. Since, according to their theory, all mental and moral phenomena are due to chemical changes and molecular disturbances in the brain, and since the child inherited a brain like its parents, the molecular movements of the child’s brain will be like the molecular movements in the brains of its parents; hence it will have inherited the mental and moral characteristics of the father and mother.