CHAPTER VIII. 

 Sterill3ing. 



Pasteurizing does not kill all bacteria as we have 

 seen, because either the temperature has not been 

 high enough, or, as is the case in the common appar- 

 atus with continuous working, has not acted long 

 enough on the milk, partly because the endurate 

 forms the spores of certain bacteria can well endure 

 temperatures of 212° F., particularly if these are not 

 kept up for a longer time. 



Investigations have shown that there exist, com- 

 paratively, not a few bacteria that are able to with- 

 stand high temperatures ; Cohrts investigations have 

 proved that the hay bacillus (bacillus subtilis) will at 

 a temperature of 120° F., at which, ordinarily, other 

 organic life commences to die, still increase rapidly, 

 and Miguel found a bacterium in water, which not 

 only endures perfectly a temperature of 158°, but 

 prospers in it ; for which reason it was named 

 " bacillus termophilus." Now, if bacteria are able to 

 resist, even in their vegetative period, the part of their 

 lives in which they, apart from a great display of activ- 

 ity and multiplication, are keenly susceptible to out- 

 ward influences, to such high temperatures which are 

 commonly considered as the limit of organic life, or, 

 if they ever require such temperatures to deploy their 



