160 ^^6 Philippine Journal of Science i9i6 



was not considered an important feature of bacterial biology at 

 that period. The Indian Plague Commission found, according 

 to the same authors, that acid was formed in dextrose, levulose, 

 mannite, and galactose, but not in lactose and dulcite. Calvert (4) 

 spoke of reddening of litmus glucose agar. Herzog(5) made the 

 statement that it does not ferment dextrose, levulose, lactose, or 

 mannite. He did not say whether this was the result of his own 

 observations nor whether the term "ferment" was intended to 

 signify gas production. It is improbable that he tested for acid- 

 ification in these media. 



The first extended tests were those of MacConkey(6) in 1905. 

 In his bile salt medium for a base he obtained acid without gas in 

 dextrose, levulose, maltose, galactose, mannite, and dextrin, but 

 no change in raffinose, lactose, saccharose, dulcite, and sorbite. 

 It is not stated how this acidity was determined. Wherry (7) 

 described the organism isolated from a plague rat as growing 

 only in the open end of fermentation tubes containing 1 per cent 

 dextrose, levulose, lactose, saccharose, and starch bouillons. 

 These cultivations were intended to rule out B. coli, and no men- 

 tion of acid formation was made. Later, however, (8) he de- 

 scribed strains from human cases and from ground squirrels, 

 all of which produced acid but no gas in 1 per cent dextrose, 

 levulose, galactose, maltose, and mannite broths, but no change 

 in lactose, saccharose, or inulin. Vourland(9) tested a single 

 strain and found that beside the sugars given by MacConkey 

 glycerin, arabinose, xylose, salicin, saccharose, and lactose gave 

 acid reactions. Dextrin, however, was not acidified, and he 

 noted that saccharose reverted to blue. 



MacConkey, (10) in 1908, reiterated his previous results, adding 

 adonite, inulin, amygdalin, and a-methyl glucoside to his list of un- 

 affected substances, and suggested that Vourland's results might 

 have been due to a possible trace of muscle sugar in the ordinary 

 nutrient agar which he employed. The Ad\dsory Committee (H) 

 confirmed some of MacConkey's reactions, having used his me- 

 dium with glucose, levulose, mannite, and galactose, which gave 

 acid, and lactose and dulcite, which were not changed. 



McCoy, (11) working in the Hygienic Laboratory in Washing- 

 ton, determined the virulence of old strains from Manila, Bom- 

 bay, Jedda, New York, Glasgow, San Francisco, and Reedy 

 Island in comparison with newly isolated strains from San Fran- 

 cisco. The old strains had been tested culturally by Wherry, 

 who had found that the activity of the cultures was alike through- 

 out — dextrose, levulose, and galactose being most actively fer- 

 mented, mannite next, and maltose least. McCoy found no 



