74 



PHARMACEUTICAL BACTERIOLOGY 



H. Gelatin Medium.- 

 Beef Extract, v 

 Gelatin, 

 Salt, 

 Peptone, 

 Distilled Water, 



3 gm. 



loo gm. 



S gm. 



lo gm. 



lOOO cc. 



Mix ingredients in a rice cooker and boil for one-half hour, stirring fre- 

 quently; titrate to +1.0 per cent, and filter. This forms a very effi- 

 cient culture medium for most bacteria, and is clear and remains solid 

 at ordinary temperatures. It must be borne in mind, however, that 

 frequent or prolonged heating tends to Uquefy gelatin permanently. 



Pig. 23. _ Fig. 24. 



Fig. 23. — MurriU's Gas Pressure Regulator. This apparatus in its most improved 

 form is to be used in connection with a thermostat for the maintenance o£ a constant 

 temperature. The use of this regulator relieves the thermostat of the necessity of caring 

 for the wide variation which is apt to occur in the gas pressure, and with it the temper- 

 ature may be held constant to within o.i° C. 



Fig. 24. — Reichert thermo-regulator or thermostat used with incubator and other 

 apparatus requiring a uniform degree of temperature. M ay be used in conjunction with 

 the gas pressure regulator. 



I. Agar Medium. — Agar is a seaweed found on the Japanese coast. 

 It forms an important article of diet among the Japanese and Chinese. 

 The medium consists of 



Beef Extract, 



Agar, 



Salt, 



Peptone, 



Distilled Water, 



3 gm- 



IS gm: 



5 gm. 



10 gm. 



1000 cc. 



