200 LABORATORY GUIDE IN BACTERIOLOGY 



Endo's Medium — 



Pepton (Witte) lo grams 



Extract of meat 3 grams 



NaCl S grams . 



Distilled water 1,000 c.c. 



Dissolve by boiling. Titrate to o . 2 per cent acid 

 to phenolphthalein. Place in autoclave at 15 pounds 

 pressure for 6 minutes. Cool and filter off precipitate. 

 Titrate again to 0.2 to 0.3 per cent acid. 



Then add: 



Agar threads 30 grams 



Boil until dissolved and make up to 1,000 c.c. 



Saturated solution of basic f uchsin 3 c.c. 



Sodium sulphite solution (5 per cent 



anhydrous) 23 . 3 grams 



Lactose (dissolved in 50 c.c. hot water) 10 grams 



Tube and sterilize in autoclave for 10 minutes at 

 10 pounds pressure. 



Russell's Medium — 



Make up 1,000 c.c. broth (meat extract) and make 

 reaction o . 9 per cent acid to phenolphthalein. Auto- 

 clave and filter. Add 15 grams thread agar and 

 dissolve by boiling. 



Add I per cent Htmus solution in proportion of 

 S per cent. 



Add sufficient n.Na^COj to bring the solution to 

 the neutral point of the litmus (12-15 c.c). 



Add I per cent lactose and o . i per cent dextrose. 



Tube and sterilize for 10 minutes at 10 pounds 

 pressure. 



The amount of Na^COj must be accurate, as other- 

 wise the medium will turn greenish after sterilizing. 



