138 THE ROYAL SOCIETY OF CANADA 



Culture 18. — Alkaline to Methyl Red; positive to the Voges- 

 Proskauer reaction. Glucose, lactose, saccharose, maltose, dulcite, 

 xylose, salicin and aesculin are fermented to acid and gas. 



Note: The fermentation of lactose is delayed, usually from two 

 to three days being required for the production of gas. 



Classification 



The organisms of this group are all to be considered as varieties 

 of the colon-aerogenes group (Escherich)^. Using the classification of 

 Jackson,^ which has since been adopted by the American Public 

 Health Association,^ we are justified in sub-dividing this group and 

 classifying as follows : 



Culture 2 as of the type B. acidi-lactici (Hueppe). 



Cultures 9 and 15 as of the type B. aerogenes (Escherich). 



Culture 17 as of the type B. coli (Escherich). 



Culture 18 as of the type B. communior (Durham). 



Group III 



Cultures 8 and 24 are members of this group. They were isolated 

 from the gills, and intestines of herrings respectively. 



Microscopically they are short rods, gram negative and motile. 



Gelatine is not liquefied; litmus milk is not changed; indol is not 

 produced; each strain is faintly acid to Methyl Red, and negative to 

 the Voges-Proskauer reaction. Both cultures ferment glucose and 

 maltose to acid and gas, the action of culture 24 being feeble and slow. 

 Gas is not produced from lactose, saccharose, mannite, dulcite, sali- 

 cin or aesculin. The action on xylose is variable. 



Classification 



These strains are of very considerable interest. They are ruled 

 out of the colon-aerogenes group on account of their inability to attack 

 lactose. They more nearly approach the type B. paratyphosus, or 

 the type B. enteritidis — (Gaertner group) — the organisms of the 

 Gaertner group being those most commonly associated with cases of 

 food poisoning; these types, however, are both able to ferment dulcite. 

 Besson' considers the organisms of the Gaertner group always fer- 

 ment dulcite. Savage,* in his numerous and valuable reports on cases 

 of food poisoning, is very definite as regards the ability of the true 

 Gaertner group to ferment dulcite to acid and gas. Jordan^ reports 

 that all the Gaertner strains with which he worked are dulcite positive. 

 Our cultures, 8 and 24, are unable to ferment dulcite to gas. Savage^" 



