The preventive treatment is carried out by medical officers of health, sanitary inspectors, nurses and health visitors, who visit the homes of notified cases, investigate home conditions and give advice in a more or less conventional way.But it often happens that a child has been notified, or a young adult, when the chief source of infection is one of the patient’s grandparents, a relative staying in the house...A notified tuberculous father may be given a room to himself, while his wife, who has chronic tuberculosis and is the source of his infection, is sent to sleep with, and infect, the children.  Or a child with enlarged glands is removed from the company of other children, some of whom have glands equally large (but unnoticed), and sent to sleep with the tuberculous grandmother.