Do not visit the sick when you are fatigued, or when in a state of perspiration, or with the stomach empty - for in such conditions you are liable to take the infection. When the disease is very contagious, take the side of the patient which is near to the window. Do not enter the room the first thing in the morning before it has been aired; and when you come away, take some food, change your clothing immediately, and expose the latter to the air for some days. Tobacco-smoke is a preventive of malaria.