68 BACTERIOLOGY. 



sterilization, or, in the particular case of wound 

 infection, antisepsis. A term commonly used 

 in connection with infectious diseases or epi- 

 demics is disinfection, meaning thereby the 

 destruction of infectious matter. A tempera- 

 ture of over 100 C gives the surest results. 

 Pure, air-free steam at a temperature of about 

 120 or at a pressure of i^ atmospheres is ordi- 

 narily employed, since no bacterial spores are 

 able to endure its action for more than half 

 an hour. Streaming steam, free from air but 

 not under pressure and at a temperature of 

 about 100, can also be used, but to be effective 

 it demands a longer time. Both these prin- 

 ciples have been embodied in the construction 

 of large, stationary pieces of apparatus and in 

 small transportable devices. By means of these 

 the whole technique of disinfection has been 

 remodeled and such processes as the sterilizing 

 of milk for children have been made possible 

 on a large scale. 



For other purposes we are able to reach the 

 same end only somewhat less conveniently 

 by long boiling, either direct or in a water- 

 bath. It is often necessary, however, as our 

 housewives know from their experience in the 

 boiling down of fruits, to repeat the heating 

 operation several times on different days. This 

 modification is called intermittent or discon- 



