APPARATUS, MATERIAL, AND REAGENTS. IQ 



The apparatus should be adjustable so that the 

 stage of the microscope may be made horizontal. 

 This will admit of micro-organisms in liquids, or 

 cultivations in nutrient gelatine on plates and in 

 capsules, etc., being photographed. Micro- photo- 

 graphy is the most satisfactory method of repre- 

 senting cover-glass, or impression-preparations. 



(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 FIG. i. KOCH'S 

 in the lower chamber ; this should STEAM -SRILISER. 

 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 



