358 THE COLI CLOACA PROTEUS GROUP 



BACILLUS CLOAOffi. 



Bacillus cloacae was isolated from sewage and polluted water by 

 Jordan. 1 The organism appears to be relatively abundant some years 

 and comparatively uncommon other years. When it is abundant in 

 sewage it is found occasionally in the intestinal tract of man. 



Morphology. The bacillus is of moderate size, measuring from 0.6 

 to 0.8 micron in diameter and from 1 to 2 microns in length. It 

 occurs singly or in pairs, uncommonly in short chains. Young cultures 

 exhibit motility, and the organisms possess peritrichic flagella. No 

 spores or capsules have been demonstrated. Ordinary anilin dyes 

 color the bacilli readily, and they are Gram-negative. 



Isolation and Culture. The colonies on agar plates after eighteen 

 hours' incubation are round, clear and colorless, and measure from 

 1 to 3 mm. in diameter. There is nothing distinctive in the appear- 

 ance of the growths. 



Products of Growth. (a) Chemical. Indol, phenol, hydrogen sul- 

 phide and ammonia are produced in sugar-free broth. The ammonia 

 production is greater than that characteristic of B. coli and less than 

 that ordinarily produced by B. proteus. 2 Acid and gas are produced 

 in dextrose, lactose, saccharose and mannite broths. The gas ratio 

 is somewhat variable, but distinctive ; the proportion of carbon dioxide 

 to hydrogen is greater than that produced by other closely-related 

 bacteria. 3 The action of the organism upon lactose is slow, and less 

 gas is produced from this sugar. The amount of gas produced from 

 dextrose and saccharose is greater than that produced by other aero- 

 genie members of the paratyphoid-pro teus group. B. cloacae forms 

 but little acid from the fermentation of sugars, and after one to three 

 days the reaction, even in sugar broth, becomes alkaline, due to the 

 exhaustion of the sugar and the subsequent decomposition of the 

 protein constituents of the broth. 4 Indol and other products of putre- 

 faction are formed as soon as the sugar is exhausted. 



Milk is coagulated and slowly peptonized. Freshly isolated cultures 

 usually liquefy gelatin, but this property is lost after prolonged artifi- 

 cial cultivation. 



The organism is ordinarily non-pathogenic for man. 



1 Annual Report of Massachusetts State Board of Health, 1890, p. 836. 



2 Kendall, Day and Walker, Jour. Am. Chem. Soc., 1913, xxxv, 1230. 

 3 H:CO 2 = - i Theobald Smith, Fermentation Tube, 1893, p. 215. 

 4 Kendall, Day and Walker, loc. cit. 



