MEDIA FOR B. COLI 717 



(6) Conmdi-Drigalski agur. Mixture A. To 1 litre of acid 

 beef broth (p. 69) add : 



Witte's peptone . . . . . .10 grin. 



Nutrose . . . . . . . 10 ,, 



Sodium chloride . . . . . 5 



Steam for one hour, and add 25 grin, of powdered agar. Steam 

 for three hours, bring to a reaction of -f- 10, and filter through 

 " papier Chardin." 



Nutrose is now unobtainable. As a substitute Mackenzie Wallis 

 recommends the following : 



Pea-nut flour . . . . . .94 parts. 



Casein ....... 5 parts. 



Sodium carbonate . . . . .1 part. 



The mixture is used in the same quantity and manner as 

 nutrose. 



Mixture B. Boil for a few minutes 100 c.c. of Kubel-Tiemann's 

 litmus solution, add 15 grm. of pure powdered lactose, and boil 

 again for a few minutes. 



Add B to A, and to this mixture add 2 c.c. of a hot 10 per cent, 

 solution of anhydrous sodium carbonate and 10 c.c. of a 0-1 per 

 cent, solution of krystal violet. The medium, either in bulk or 

 tubed, is then sterilised. 



(7) Neutral-red bile-salt agar. " Kebipelagar," as he terms it, 

 has been used by Houston for the isolation of B. coli. It has the 

 following composition : Agar 20 grm., taurocholate of soda 5 grm., 

 lactose 10 grm., neutral-red 4 c.c. of a 1 per cent, solution, peptone 

 20 grm., water 1 litre. The 8.D.8. rebipelagar has the following 

 composition : Agar 20 grm., taurocholate of soda 5 grm., lactose 

 2-5 grm., neutral-red 4 c.c. of a 1 per cent, solution, peptone 

 20 grm., saccharose 2-5 grm., dulcitol 2-5 grm., salicin 2-5 grm. 



(8) Fuchsin agar (Endo). One litre of 3 per cent, nutrient agar 

 is made alkaline with 10 c.c. of 10 per cent. NaOH solution after 

 neutralisation. Pure lactose 10 grm. and saturated alcoholic 

 fuchsin solution 5 c.c. are added, and after mixing, 25 c.c. of 

 fresh 10 per cent, solution of sodium sulphite are added. The 

 medium when cold should be colourless. The medium is used as 

 surface plates, and on it typhoid and paratyphoid colonies are 

 colourless, coli colonies are red. 



