=What one receives at birth constitutes his heredity.=--This consists of a normal or defective physical constitution, the natural bent of mind and its rudimentary possibilities and the innate tendencies toward good or evil. The physical, mental and moral influences one receives after birth constitute his environment. Ideal environment tends to direct, develop and to mature the results of good heredity and to correct the results of bad heredity. Bad environment tends to neutralize the effects of good heredity and to intensify the effects of bad heredity. If a child has inherited a frail constitution, this can be overcome largely or entirely by proper physical training, appropriate food and observing other health laws. In such cases, heavy drugging will do but little good. If nature is aided by intelligent parents, who have inspired their unfortunate child with an intense interest and purpose to out-grow every defect, he will accomplish wonders. If a child has inherited a tendency toward tuberculosis, this can be entirely overcome by physical training, deep breathing, nutritious food and ventilated bed rooms. The same is true of many other physical defects. =Our mental possibilities are largely inherited.=--Schools and colleges do not produce great minds. They direct, train and develop the inherited mental possibilities. Children of mediocrity should have every possible encouragement and opportunity for mental improvement. They cannot succeed without it. Their offspring will inherit improved mental possibilities, if their parents are wisely trained in childhood. Children who have inherited special genius will succeed in spite of limited opportunities, but they will succeed better by having the advantage of a good education. A practical study of the psychology of childhood, in relation to mental heredity, would lead parents and teachers to be more patient, sympathetic and wise in the mental training of many children. =Heredity and moral tendencies.=--Heredity is just as potential in the moral realm as in the physical and mental. Children inherit tendencies toward good or evil, virtue or vice. What they inherit morally is determined by the relation of their ancestors to moral laws.