BACTERIOLOGICAL DATA. 41 



tubes, prepared according to the formula used by Russell.^ Of the 

 15 cultures thus inoculated, 5 showed reactions corresponding to 

 Russell's description of the typhoid organism and were submitted to 

 the writer for identification. One of these 5 cultures was subsequently 

 found to be B. typhosus and confirmed as above described. The 4 

 other cultures were discarded because they were feebly motile; no 

 attempt was made to rejuvenate or increase their motility. 



The organisms described as paratyphoid and paracolon were 

 classified wholly from their morphological and biological character- 

 istics on differential media, including their reaction on RusselFs 

 double sugar litmus agar, dextrose, lactose, and saccharose fermenta- 

 tion tubes, milk, etc. No agglutination tests were made on these 

 strains. In addition to these organisms a strain resembling B. 

 alcaligenes was also recovered and studied in the same manner as 

 were the others. 



After having been out of water for 21 days at 39° F., oysters from 

 the same lot that contained the typhoid bacilli were examined by 

 the author. A large number of strains of organisms were isolated 

 from 24-hour Endo's plates, prepared directly from the shell liquor 

 of these oysters, and transferred to Russell's double sugar agar tubes. 

 Of the cultures showing reactions for B. typhosus on this medium, 

 further study was made on differential media and by agglutination 

 tests. 



One strain resembling B. typhosus thus isolated was at first only 

 moderately motile, but it possessed all the other biological charac- 

 teristics of typhoid bacilli. Its motility was greatly increased by 

 growing on gelatin for two generations. The agglutination tests 

 were made by using one-day gelatin stock cultures grown at room 

 temperature. These tests were made in dilutions of 1:1,000 macro- 

 scopically, and confirmed in hanging drop preparations in dilutions 



1 Russell, F. F. The Isolation of Typhoid Bacilli from Urine and Feces, with the Description of a New 

 Double Sugar Tube Medium. (Reprinted from The Journal of Medical Research, vol. 25, No. 1.) Enough 

 5 per cent aqueous solution of litmus is added to plain agar (2 per cent to 3 per cent) , with a reaction of about 

 +0.8 per cent to phenolphthalein, to give it a distinct purple violet color, the amount of litmus depending 

 on color of agar (dark requiring more than the light), and the reaction is then adjusted by addingtsodium 

 hydrate until the mixture is neutral to litmus. Then 1 per cent of lactose and 0.1 per cent of glucose are 

 added, dissolved !in a small amount of hot water, and the medium tubed as for slants. After tubing, pack: 

 slants loosely in basket and sterilize them for 10 minutes on first day and 15 minutes on second day in an 

 Arnold sterilizer; then slant and store in dark place. 



On this double sugar tube the typhoid bacillus gives, after an incubation period of from 8 to 18 hours, an 

 extremely characteristic appearance; the surface growth is filiform and colorless on a blue background; 

 the upper part of the tube is unchanged in color, but the lower part, the butt, is a brilliant uniform red. 

 The entire point of the medium rests upon the difference between the changes produced by the growth of 

 the typhoid bacillus under aerobic and those produced under the imperfect anaerobic conditions found in 

 the butt of the tube, where the baciUus obtains its oxygen by breaking down the glucose, with the libera- 

 tion of considerable acid,5 on the surface, however, in the presence of free oxygen, no acid is formed. 



The colon bacillus, wtich is often slow in producing acid on the Endo plate, shows abundant gas and 

 acid formation on this medium. The tube is reddened throughout, both above and below, and since the 

 abundant lactose is attacked equally with the glucose there is exuberant gas formation. 



The Bacillus fecalus alcaligenes and other alkali formers leave the medium unchanged or slightly bluer. 



