SPECIAL EXAMINATIONS 353 



aerogenes, B. acidi lactici, B. neapolitanus, B. icter- 

 oides, B. psittacosis, B. cloacae, B. proteus vulgaris, 

 bacillus of hog cholera, bacillus of epidemic jaundice, 

 B. oxytocus perniciosus, and B. capsulatus. 



Group 2. Bacteria producing acid, but not gas. 



B. typhosus, B. dysenteriae, B. cholerae, B. pyo- 

 genes fcetidus, streptococci and staphylococci. 



The first group can be subdivided into four : 



(a.) The proteus group of motile bacilli : gelatin-lique- 

 fying, form acid and gas in glucose, maltose, saccharose, 

 and galactose, but not in lactose, laevulose, arabinose, 

 rafhnose, mannite, sorbite, dulcite, adonite, dextrin, starch, 

 or inulin ; curdle milk slowly with acid ; commonly produce 

 indol in peptone solutions. 



(b.) B. coli communis family : motile bacilli, non-gelatin- 

 liquefying, producing acid and gas in all the above except 

 saccharose, adonite, starch, or inulin ; curdle milk rapidly 

 with acid, but do not peptonize clot ; form indol. 



(c.) B. lactis aerogenes group : non-motile bacilli, non- 

 gelatin-liquefying, producing acid and gas in all the above 

 except three dulcite, adonite, and inulin ; curdle milk 

 rapidly with acid ; do not peptonize clot ; form indol. 



(d.) The paracolon-enteritidis series : motile bacilli, non- 

 gelatin-liquefying, producing acid and gas in all but lactose, 

 saccharose, adonite, starch, or inulin ; do not clot milk 

 but finally render it alkaline ; do not form indol. 



III. Isolation of B. Coli. 



(a.) From each tube showing acid and gas, and acid 

 alone, make a surface smear with one platinum loopful on 

 a plate of neutral red, bile salt, peptone, lactose, agar (rebi- 

 pelagar) containing 1 part of crystal violet in 10,000. 

 Incubate these plates for twenty-four hours at 37 C. 



(b.) Examine thereafter. If a plate shows only one kind 

 of colony, inoculate an agar slope from a mixture of these. 

 If more than one form of colony is seen on any plate, 

 inoculate agar slopes from each kind of colony. Incubate 

 the various inoculated agar tubes (properly marked or 

 labelled) at 37 C. for twenty-four hours. This growth on 

 agar gives sufficient material for subsequent steps ; but 

 it is also necessary to revive any fermentative powers 



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