INOCULATION OF GELATIN AND AGAR 



ized in the hot-air oven at a temperature of 150 C. for ten 

 minutes (Fig. 31). When the plates have cooled, they are 

 placed upon an apparatus designed to cool and solidify the 

 liquid media, which is now poured upon 

 the plates from the inoculated test-tubes. 



Nivellier Leveling and Cooling Ap 

 paratus. Ice and water are placed in a 

 shallow round glass tray; on top of this a 

 square plate of glass, upon which 

 culture-plate is placed, and covering this, 

 a bell-glass. 



The whole is upon a low wooden 

 tripod, the feet of which can be raised 

 or lowered, and a little spirit-level used 

 to adjust it (Fig. 32). The glass plate 



Fig. 31. Iron box for 

 glass plates. 



taken out of the iron box is placed under the bell-glass. The 

 tube containing the gelatin is held in the flame a second to 

 singe the cotton plug to free it from dust, and the plug 

 removed, the edges of the tube again flamed, the bell-glass 



Fig. 32. Nivellier leveling and cooling apparatus. 



lifted, and the inoculated gelatin carefully poured on the 

 plate, leaving about one-third inch margin from the borders; 

 the lips of the tube being sterile, can be used to spread the media 

 evenly. If the plate is at all cool, the fluid will solidfy as it is 

 being spread. The glass cover is replaced until the gelatin or 

 agar is quite solid, to prevent contamination. 



