BACTERIOLOGICAL TECHNIC. 



47 



J. A gar-gelatin Medium. This has the advantage of both media, and is 

 now much used in general bacteriological work. 



Agar, 

 Gelatin, 

 Salt, 

 Peptone, 

 Distilled Water, 



8 gm. 

 40 gm. 



5 gm. 

 10 gm. 



IOOO C.C. 



Mix, boil in rice cooker, stir; neutralize, filter, and sterilize as for other 

 media. 



The above includes the more important culture media used in bacteriolog- 

 ical work. Others can be prepared as occasion requires. It is not neces- 



FIG. 23. 



FIG. 24. 



FIG. 23. MurrilPs Gas Pressure Regulator. This apparatus in its most improved 

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

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

 for the wide viriation which is apt to occur in the gas pressure, and with it the temperature 

 may be held constant to within 0.1 C. 



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

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

 the gas pressure regulator. 



sary to make up the full amounts indicated if it is evident that smaller 

 quantities will suffice. The student should prepare all of the media in small 

 amounts (one-quarter the quantities given) several times, in order to get 

 the necessary experience and practice. 



6. General Directions for the Preparation of Culture Media. 

 Book information alone is not sufficient. Experience must be added. 



