APPARATUS, MATERIAL, AND REAGENTS. 1 9 



organisms. Numerous preparations have been 

 satisfactorily depicted by means of the isochromatic 

 plates without any reference to the staining reagents 

 employed. For a full description of the apparatus 

 and methods employed the reader is referred to 

 the author's publication.* 



(F) STERILISATION APPARATUS. 



Steam-Steriliser. A cylindrical vessel of tin 

 about half a metre or more in 

 height, jacketed with thick felt, 

 and provided with a conical cap 

 or lid (Fig. i). The lid is also 

 covered with felt, has handles on 

 either side, and is perforated at 

 the apex to receive a thermometer. 

 Inside the vessel is an iron grating 

 or diaphragm about two-thirds the 

 way down, which divides the interior 

 into two chambers the upper or 

 "steam chamber," and the lower 

 or " water-chamber.' ' A gauge 

 outside marks the level of the water . ~F IG . i. KOCH'S 



,11 i i ,1 1 u STEAM-STERILISER. 



in the lower chamber ; this should 

 be kept about two-thirds full. The apparatus 

 stands upon three legs, and is heated from below 

 with two or three Bunsen, or better, a Fletcher's 



* Photography of Bacteria. 1887. 



