154 GENERAL PHYSIOLOGY 



getting this apparatus, a good-sized metal pail can be used, 

 but it is best to place this in a metal washtub or on a piece of 

 asbestos of some size. There is by this method considerable 

 danger of spurting, due to the violent chemical action which 

 goes on. It is therefore undesirable to use more than three 

 pounds of permanganate in one receptacle ; if more is needed, 

 it is best to have another container. The room or apartments 

 should remain closed at least eight hours; it will then be pos- 

 sible for some one to rush in and open up a window, and then 

 as soon as possible the space should be thoroughly aired, and, 

 if thought necessary, the odor can be neutralized by the use of 

 ammonia. 



All disinfection ought to be tested by means of cultures. 

 The test is a very simple one. A standard organism, such as 

 M. pyogenes var. aureus, is spread on sterile squares of cotton 

 cloth, allowed to dry, and put in a sterile test tube. This 

 sterile test tube is placed in the room and the cotton plug 

 removed. After disinfection the test outfit is taken to the 

 laboratory and the cotton cloth is then dropped into culture 

 media. If the media remain sterile, the process of disinfec- 

 tion was satisfactory, otherwise it is to be repeated. 



