370 



APPLIED BACTERIOLOGY 



cold water. Thick objects are removed for drying to a 

 separate closet, which may be heated by the waste steam 

 from the disinfector. 



The Testing of Steam Disinfectors. — Steam disinfectors 

 may be examined either directly, by determining the 

 exposure necessary for the destruction of test organisms, 

 or indirectly, by measuring the temperature and other 

 physical quantities. The direct method is unsatisfactory, 



Fig. 36. — Beck's Disinfector. 



owing to the wide variability which specimens of appar- 

 ently the same organism may display through circum- 

 stances such as age of culture, presence of interfering 

 media, etc., of which the variations cannot be measured, 

 and of which even the qualitative effect cannot always be 

 stated in general terms. In such an examination it is 

 therefore impossible to take a given organism as com- 

 parable with the same organism used in previous experi- 

 ments ; and for it to have value, the inquiry must include 



