88 BACTERIOLOGY 



of which is somewhat larger in circumference than the 

 remaining four-fifths and serves as a reservoir for the water 

 from which the steam is to be generated. Covering this 

 section of the cylinder is a wire rack or grating, through 

 which the steam passes, and which supports the articles to 

 be sterilized. Above this, comprising the remaining four- 



FIG. 8 



Steam sterilizer, pattern of Koch. 



fifths of the cylinder, is the chamber for the reception of 

 the materials over and through which the steam is to pass. 

 The cylinder is closed by a snugly fitting cover, through 

 which are usually two perforations, into which a thermo- 

 meter and a manometer may be inserted. The whole 

 of the outer surface of the apparatus is encased in a non- 

 conducting mantle of asbestos or felt. 



