Diphtheria is not directly caused by unhygienic surroundings. A disregard for hygiene disposes a child for infection if the child is exposed to the bacillus. The specific germ must be introduced into the patient's mouth or nostrils. When a child is infected with diphtheria the breath is not a medium of contagion. The sputum, spat out or coughed out, is a means whereby the disease is spread. The bacillus is in the patient's mouth and nostrils; it gets upon his hands by contact, upon eating utensils, upon whatever touches the mouth of the sick person. The bacillus does not float in the air of even the sick-room, except in those cases where dried sputum is stirred up by sweeping or attrition of other kinds. In a boarding-school or family when a diphtheria patient is found, select a room set off as far as possible from the rooms commonly used, and before putting the patient into this room remove all curtains, upholstered furniture and carpets from it that are not so cheap or so worn that they may be destroyed after the patient's convalescence, or which are of such texture that they will not be destroyed by water or disinfection by heat. In any case the less there is in the room the easier the disinfection will be. Use the mattress upon which the patient had slept before you discovered the nature of the disease. Books should be removed, because an infected book can not be disinfected except upon the outside. The room is not to be swept while the patient is in it,--dust may be wiped up with a damp cloth. The cloth is to be disinfected before it is sent out of the room. The popular notions regarding sulphur as a disinfectant after diphtheria are erroneous. Sulphur fumes in certain definite quantities will disinfect after smallpox, scarlet fever, measles, and some other diseases; these fumes will also kill the diphtheria bacillus, if the bacillus is wet and exposed directly; but if it is buried in sputum or in clothing the fumes will have no effect whatever upon it. The disinfectants to use are acid bichloride of mercury and heat. Formaldehyde does not penetrate well enough to be reliable in diphtheria. {191}