STERILIZATION BY MOIST HEAT “123 
of acid. Chick (1910) states, “ The striking similarity between the 
effects of temperature (dry) on the one hand and hot water on the other 
indicate that disinfection by the latter is due to the action of water 
(coagulation and alteration) upon some one protein which is essential 
for life of the bacterium and that the reaction is conditioned by the 
chemical action of water upon its constituent proteins.” The follow- 
INLET OF AIR 
f1a. 37.—Hot-air Sterilizer, Lautenschlager Type 
ing facts with regard to disinfection by moist heat were established 
by Chick: 
1. Disinfection proceeds according to the logarithmic law the rate 
of disinfection being proportional, at any moment, to the concentration 
of surviving bacteria. 
2. The presence of minute quantities of acid or alkali too small to 
produce any direct disinfectant action increases the reaction greatly. 
The acid, however, gave the greatest increase. This presents close 
analogy to the “ heat coagulation ”’ of proteins. 
