It would be desirable to ascertain the existence of onanism before its effects appear; but this is seldom the case. There is in children a kind of instinct which leads them to conceal this manœuvre, although they have not learned that it is an illicit act. The art with which they elude vigilance is often inconceivable. Watch where the child goes. Have an eye to him who seeks solitude--who remains a long time alone, and who cannot give a good account of himself. Be watchful about the periods of lying down and of rising. At this time, the onanist may be detected in the act. His hands are never out of bed, and his face is often hidden under the bed-clothes. Soon after lying down, he appears sound asleep: this circumstance, which always causes distrust in the experienced man, is one of those which contribute the most to inspire the parents with a feeling of security. The affectation of sleep in the young person may serve to detect him. When approached, he is frequently found red, and covered with sweat, although neither the temperature of the chamber, the weight of bed-clothes, nor any other cause, can explain this state: at the same time, the respiration is more hurried, the pulse is fuller, harder, and more frequent; the veins are larger, and the heat is greater, than usual; in fine, there is that kind of fever, of general turgescence, which usually attends the act of venery. When the young person is disturbed suddenly, his hands, if he has not had time to remove them, will be found on or near the genital organs. The penis, also, may be found in a state of erection; or you may even find marks of recent pollution, which might be known by the peculiar odor arising from the semen, and which comes from the soiled fingers. Have an eye to those young persons, whose hands, when in bed, or during sleep, are in the position described: they are onanists, or will become so. The same is true in those who frequently have erections of the penis. This erection, and this attitude, are certainly not positive signs of onanism; but they are the probable, or precursory signs of it: they should not, then, be neglected. The stains of semen, on the bed-clothes or dress, may also increase suspicion. When the patients are very young, they are not very evident, the fluid which they emit not having the characters of real semen: the traces which it leaves, however, are too remarkable, not to cause suspicion as to their origin. In those who have attained the age of puberty, there would be nothing equivocal: the only question then would be, that they might be produced by involuntary pollution. On this topic, we would remark, that this pollution seldom occurs before the age of fifteen or sixteen years, and is seldom frequent before twenty. When involuntary discharges of semen are frequent in young persons, you may be assured that they are the indirect results of onanism: hence, there is reason to regard stains of semen as positive proofs of onanism, when the