132 CULTURE MEDIA AND THEIR STERILIZATION 



Sugar Gelatin or Sugar Agar. This is prepared like the ordinary 

 gelatin or agar plus the addition of generally 1 to 2 per cent, 

 glucose, lactose, maltose, saccharose, etc. 



FIG. 67 



Adjustable copper trays for slanting agar or blood-serum tubes. 



Agar slants ready for use. 



Glucose Formate Gelatin (Kitasato). Ordinary gelatin plus 2 per 

 cent, glucose and 0.4 per cent, of sodium formate. 



Litmus Gelatin. Ordinary nutrient gelatin plus a sufficient quan- 

 tity of sterile litmus solution to give it a lavender color. 



Lactose Litmus Gelatin. Ordinary nutrient gelatin plus 2 per cent, 

 lactose plus a sufficient quantity of sterile litmus solution to give the 

 transparent culture medium a pale lavender color. 



Glycerin Agar. Prepare nutrient bouillon as usual, but add finally 

 50 c.c. of pure neutral glycerin for each 1000 c.c.; then treat the agar 

 as described above. 



Sugar Agar. Nutrient agar plus 2 per cent, glucose, lactose, maltose, 

 saccharose, etc. 



