3 02 



METHODS OF IDENTIFICATION AND STUDY 



(a) 



Thermometer to 120 C., its bulb immersed in the normal 

 saline. 



Straight entry tube, reaching to the bottom of the flask, 

 the upper end plugged with cotton-wool. 

 Bent syphon tube, with pipette nozzle attached by means 

 of rubber tubing and fitted with pinch-cock. 

 The nozzle is protected from accidental contamination by 

 passing it through the cotton-wool plug of a small test-tube. 



(c) 



FIG. 156. Apparatus arranged for the determination of the death-point of 



spores. 



(d) A sickle-shaped piece of glass tubing passing just through 

 the stopper, plugged with cotton-wool, to act as a vent 

 for the steam. 

 Sterile plates. 

 Sterile pipettes. 



Sterile test-tubes graduated to contain 5 c.c. 

 Media Required: 

 Gelatine or agar. 

 Culture flasks containing 200 c.c. nutrient bouillon. 



METHOD. 



i. Prepare twelve tube cultivations upon the sur- 

 face (or two cultures in large flat culture bottles 



