200 LABORATORY GUIDE IN BACTERIOLOGY 



Endo's Medium 



Pepton (Witte) 10 grams 



Extract of meat 3 grams 



Nad 5 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 fuchsin 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 litmus solution in proportion of 

 5 per cent. 



Add sufficient n.Na 2 CO 3 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 3 CO 3 must be accurate, as other- 

 wise the medium will turn greenish after sterilizing. 



