Unfortunately, even a moderate heat cannot always be applied. One's hands, for example, can neither be heated in an oven to the necessary temperature for destroying bacteria in their pores, nor can they be immersed in boiling water or steam for a sufficient time to secure thorough disinfection. Therefore, with the body, chemical means for disinfection must be employed. Also when it is desired to disinfect a liquid, such as beef broth, in which the experimenter desires to grow some particular species to the exclusion of all others, dry heat is inapplicable because it would evaporate the liquid, nor is chemical disinfection possible because of its antiseptic effect on the bacteria to be cultivated. Moist heat, therefore, must be used. When dry heat is used, it is usually for the disinfection of glassware or earthenware or metallic objects, the quality of which will not be affected by the necessary temperature, namely, 150 degrees Centigrade, or about 300 degrees Fahrenheit. This temperature must be maintained for at least an hour, and it is not certain even then to penetrate in full power to the middle of blankets or comfortables. Except for glassware to be used in a laboratory, dry heat, such as would be obtained by a kitchen oven, is not to be recommended. _Boiling water._ Boiling water, on the other hand, is the most effective and penetrating disinfecting agent available. One has only to expose an object to boiling water for five minutes to absolutely kill all disease-bearing bacteria contained, and since bed linen, clothes, blankets, and such articles as are naturally used in a sick room have to be washed after a patient's recovery, it requires but very little additional trouble to subject the soiled articles to that temperature of the water which will secure disinfection at the same time. But the water must be boiling. The mere fact that it was once boiling water gives it, half an hour later, no disinfecting properties, and complete disinfection can be secured only by actually boiling the garments or articles for at least five minutes. The apparatus necessary therefore--and no better piece of disinfecting apparatus can be secured anywhere--is a good old-fashioned wash boiler. The action is more certain, that is, more penetrating, if a little washing soda is added to the water at the rate of a tablespoonful of soda to a gallon of water. This solution is admirable for washing dishes, spoons, knives, forks, and other eating utensils used by sick persons. It is always a mistake to wash dishes from the sick room in the same vessel with other dishes. They should not only be washed separately, but they should be washed in boiling water, and preferably in a soap solution as just described. _Steam._