THE PREPARATION OF CULTURE MEDIA 163 



Eosin 3/50 per cent 



Brilliant green 1/300 per cent 



Saccharose 1 per cent 



Lactose 1 per cent 



The typhoid colonies on this medium are large and have a grayish pink 

 color. Most strains of B. coli do not grow upon it; the colonies of B. coli 

 that do develop have deep red centers. Meyer and Stickel 31 claim that 

 better results are obtained with the brilliant green-eosin medium if peptic 

 digest agar is substituted for the meat infusion agar. They set their reaction 

 at P ff =7 to 6.8. 



Malachite-Green Bouillon (Peabody and Pratt). 32 To 100 c.c. of beef 

 infusion broth add 10 c.c. of one per cent solution of malachite green Hochst 

 120, made with sterile water. This is tubed. 



This medium is used as an enriching fluid. One drop of the suspected 

 material (emulsified stool) is added to each tube and after incubation for 

 eighteen to twenty-four hours inoculations may be made upon plates. 



Peabody and Pratt found a reaction of .5 per cent acidity to phenol- 

 phthalein most favorable. 



Lead Acetate Agar for the Differentiation of Paratyphoid "A" and "B." 33 

 One drop of a ten per cent solution of neutral lead acetate is added to 

 every 4 c.c. of agar. This is the original procedure of Burnet and Weissen- 

 bach. Krumwiede recommends the cooling of the agar to 60, then adding 

 enough of a 0.25 per cent basic lead acetate solution to bring the concentration 

 to 0.05 per cent. The agar is tubed, and Burnet and Weissenbach recommend 

 inoculating with a fine needle in several places between the agar an_d the 

 walls of the tube. Typhoid and paratyphoid "B" bacilli blacken the medium, 

 while paratyphoid "A" leaves it unchanged. B. Enteritidis and Typhi 

 Murium behave like paratyphoid "B." 



Bile Medium?* (Recommended for blood cultures by Buxton and Cole- 

 man.) The medium is prepared as follows: 



Ox-bile 900 c.c. 



Glycerin 100 c.c. 



Pepton 20 grams 



.t into small flasks containing quantities of about 100 c.c. .each and sterilized 

 ; fractional sterilization. 

 Jackson's Lactose-Bile Medium. This medium is used for isolating B. 



31 Meyer, K. F., and Sticlce I, J. K., Jour, of Infec. Dis., 23, 1918, 48. 

 3 - Peabody and Pratt, Boston Med. and Surg. Jour., clviii, 7, 1008. 



33 Burnet and Weissenbach, C. R. de la Soc de Biol., vol. 78, 1915, p. 565. 



34 Conradi, Dent. med. Woch., 32, 1906. 



35 JacJcson, "Biol. Studies of Pupils of W. T. Sedgwick," 1906, Univ. Chicago 

 ?ress. 



