58 



RIICRO-ORGANISMS AND DISEASE [chap. 



into the lower dish so as to form a thin layer at its bottom ; 

 the lifting off of the dish-cover, the pouring in of the gelatine, 

 and the replacing of the cover, ought to occupy only a 

 moment. In order to allow the gelatine to set rapidly the 

 dish is placed on moist blotting-paper; in hot weather a few 

 bits of ice are placed on the paper. 



Fig. II.— Plate-Cultivation. 

 I Glass plate, 



2. Bell-glass. 



3. Wet filter paper. 



4. Glass dish containing the plate cultivation on a thin layer of nutritive gelatine. 

 This glass dish is covered by a second glass dish. 



This plate is then placed in the incubator as such or on a 

 glass plate, to which by means of greased edge, a bell-glass 

 can be fixed, on the interior of which is a piece of wet 

 blotting-paper. In this way a closed moist chamber is 

 established. But this is only of use if the plate is to be 

 kept in the incubator for a long time ; for ordinary work the 

 plate is placed in the incubator without further addition. 



