CHAPTER VII 

 STERILIZATION BY HEAT 



In making use of heat to destroy bacteria the method 

 employed depends largely on the character of the mate- 

 rial to be sterilized. Heat may be used in the form of 

 fire, i. e., the naked flame, or as dry heat, or as boiling 

 water, or live steam, or live steam under pressure. 



(1) Fire. — Many infected articles which it is desired 

 to be rid of can be burned in the fire, thus absolutely 

 destroying the infectious bacteria. Infected mattresses, 

 rugs, books, papers, and magazines, toys, pus-soaked 

 dressings, paper sputum cups and paper handker- 

 chiefs, and other similar articles are often best disposed 

 of in this way. In an emergency it is sometimes very 

 convenient to sterilize a knife or other surgical instru- 

 ment by passing it through the flame, or by dipping it 

 into alcohol and then lighting the alcohol. 



(2) Dry Heat — In many instances the use of fire is 

 out of the cjuestion. In such cases we may often employ 

 dry heat to advantage. In bacteriologic laboratories 

 special ovens arc constructed for sterilizing glassware, 

 etc., by means of dry heat. In the home the oven of the 

 kitchen stove will usually answer equally well. The 

 temperature of the oven should range about 300° F., 

 and the articles should remain exposed for about an 

 hour. 



