318 THE ALCALIGENES DYSENTERY TYPHOID 



cold. Cultures may retain their viability in the ice-box, 6 to 10 C., 

 for nearly two months. In sterile water the organisms at ordinary 

 temperatures do not as a rule survive more than a week. Pfuhl 1 has 

 found that dysentery bacilli may remain alive for 101 days in moist 

 soil protected from sunlight; in dry soil under otherwise the same 

 conditions they do not survive more than thirty days. In cheese and 

 in butter they remain alive for at least nine days, and in sterile milk for 

 about three weeks. Dried on linen, they also survive about three weeks. 



Products of Growth. Chemical Products. Plain broth cultures of 

 Shiga and Flexner bacilli do not contain indol or phenols, even after 

 prolonged incubation. The statements with reference to indol produc- 

 tion in the group, however, are somewhat conflicting, particularly 

 with reference to the Flexner type of organism. Morgan and others 2 

 have stated that Flexner bacilli produce indol; on the other hand, 

 Kendall, Bagg, Day and Walker 3 have isolated over 200 strains of 

 Flexner bacilli from dysenteric cases and have found almost without 

 exception that indol is not formed. These strains were identified by 

 their cultural reactions and by agglutination with specific Flexner 

 serum of high potency. Dopter 4 has found that strains of Flexner 

 bacilli obtained from different sources, which were identical culturally 

 and agglutinated the same with specific sera, vary in indol production 

 some producing indol, others not producing it. 



Acid Production in Carbohydrate Media. All members of the dysen- 

 tery group agree in two important characteristics: they do not form 

 gas in carbohydrate media, and form acid in dextrose. Lentz 5 has 

 called attention to an important cultural differentiation of the Flexner 

 and Shiga bacillus, the former producing acid in mannite, the latter 

 not fermenting this alcohol. Further study has shown that the fer- 

 mentation of various carbohydrates is important in the recognition 

 of the various types. The fermentation and other cultural reactions 

 of members of the dysentery bacillus group are shown in the table on 

 page 316. The members of the dysentery group produce an initial 

 acidity in milk; fermentation of the small amount of dextrose, amount- 

 ing to about 0.1 per cent., which is found in fresh milk (Theobald 

 Smith 6 ) followed by an .alkaline reaction (action of the organisms 

 upon protein when the utilizable carbohydrate is exhausted). 7 



i Ztschr. f. Hyg., 1902, xl, 555. 2 Brit. Med. Jour., April 6, 1907, 908; July 6, 16. 



3 Boston Med. and Surg. Jour., 1911, clxiv, 301; 1913, clxix, 741, 753; Jour. Am. 

 Chem. Soc., 1913, xxxv, 1211. 



4 Les Dysenteries, Paris, 1909, 36. 6 Ztschr. f. Hyg., 1902, xli, 559. 



5 Boston Jour. Med. Sci., 1897, ii, 236; Jones, Jour. Inf. Dis., 1914, xv, 357. 



7 See Kendall, Day and Walker for essential analytical details, Jour. Am. Chem. 

 Assn., 1914, xxxvi, 1940, 



