126 APPENDIX. 



NEUTRAL RED BROTH. 



To neutral broth is added 0.5 per cent dextrose and 

 1 per cent of a 0.5 per cent aqueous solution of Griibler's 

 neutral red. Sterilize at ioo°. 



MacConkey's Media. 



A. Agar. 



Agar 1.5 grams 



Sodium taurocholate (pure) 0.5 gram 



Peptone 2.0 grams 



Water 100.0 c.c. 



This is boiled, clarified, and filtered as usual, then 

 1.0 gram lactose is added, and the medium tubed and 

 sterilized for three successive days at ioo°. 



B. Broth. 



Sodium taurocholate (pure) 0.5 gram 



Peptone 2.0 grams 



Glucose 0.5 gram 



Water 100.0 grams 



Boil, filter, and add sufficient neutral litmus, fill fer- 

 mentation-tubes, and sterilize at ioo°. 



Litmus Solution. — To one-half pound of litmus cubes 

 add enough water to more than cover, boil, and decant 

 off the solution. Repeat this operation with successive 

 small quantities of water until from 3 to 4 liters of water 

 have been used and the cubes are well exhausted of color- 

 ing matter. Pour the decantations together and allow 

 them to settle overnight. Siphon off the clear solution. 

 Concentrate to about 1 liter and make the solution de- 

 cidedly acid with glacial acetic acid. Boil down to about 



