The danger of infection from tuberculous house servants has not been sufficiently appreciated. A chronic cough in the case of a servant should be at once investigated by the family physician. Servants should be taught the necessity for washing the hands before touching the food or cooking utensils. The condition of their rooms, clothing, bathing, and other personal habits should be closely investigated, and personal cleanliness should be demanded as a _sine qua non_ for obtaining or keeping a situation. Since it is a well-known fact that tuberculosis can be acquired from the occupation of houses and rooms formerly occupied by tuberculosis patients, it has been suggested that a clean bill of health should be demanded of the owner of the house before renting it; that is, a certificate from the Board of Health, that no case of infection has existed in the house, or that it has been properly disinfected since that time. If such a movement became popular, landlords would be obliged to furnish these bills of health in self-defense. Since the Boards of Health demand the reporting of all cases of tuberculosis, this scheme is by no means impracticable or Utopian. The tubercle bacillus is not destroyed by any degree of cold, but both light and sunlight are distinctly injurious to these bacteria. The lowest fatal temperature to the tubercle bacillus is 131° F. of moist heat, acting for a period of six hours. The thermal death-point of tubercle bacilli in milk is of great practical importance, and many experiments have been made which have determined that a temperature of from 140° to 167° F., was sufficient if continued for one hour. If it is desired to pasteurize the milk, it should be placed in a closed bottle or stirred and heated for at least twenty minutes at a temperature of 149° F. _Disinfection._—The use of formaldehyd gas has practically displaced the use of sulphur for the fumigation of rooms, as well as for the disinfection of furniture and clothing. For this purpose a moist vapor used in a sealed room is essential.