664 Bacillus Suipestifer 



the repeated examination of i cc. samples shows the presence of 

 numerous colon bacilli, the water is seriously polluted and doubtfully 

 potable, but when samples of i cc. are without colon bacilli or contain 

 very few, the water is safe. 



Another important matter in regard to the colon bacillus in water 

 is the presence or absence of certain characters by which one can 

 judge how recently it has ended its intestinal parasitism and taken up 

 a saprophytic life. The chief of these characters is the ability to fer- 

 ment lactose. Only recently isolated organisms manifest this fer- 

 mentative power in the laboratory, so that when organisms capable 

 of fermenting lactose are found, one can suppose that they result 

 from recent sewage pollution. 



Many media have been recommended for the rapid detection of the 

 colon bacilli in water, the favorite at the present time probably be- 

 ing the litmus-lactose-agar (q.v.) of Wiirtz.* This depends upon 

 the fermentative and acid-producing power of the bacillus, which is 

 shown through the presence of red colonies (acid producers) on the 

 elsewhere blue plate. These red colonies are then fished up and 

 transplanted to appropriate media for further study. 



Other media and methods useful in studjnng the colon bacilli are 

 also discussed in the chapter upon Typhoid Fever (q.v.). 



Bacillus Enteritidis (Gartner) 



General Characteristics. — A motile, flagellated, non-sporogenous, non-chro- 

 mogenic, non-liquefying, aerogenic, aerobic and optionally anaerobic, pathogenic 

 bacillus staining by the ordinary methods, but not by Gram's method. 



This bacillus was first cultivated by A. Gartnerf from the flesh of a cow 

 slaughtered because of an intestinal disease, and from the spleen of a man poisoned 

 by eating meat obtained from it. The bacillus was stibsequently found by 

 Karlinski and Lubarsch in other cases of meat-poisoning. 



Morphology.' — The baciUus closely resembles Bacillus coli communis. It is 

 short and thick, is surrounded by a slight capsule, is actively motile, and has 

 flageUa. 



Staining. — It stains irregularly with the ordinary solutions, but not by Gram's 

 method. It has no spores. 



Cultivation. — Upon gelatin plates it forms round, pale gray, translucent col- 

 onies. It does not liquefy the gelatin. The deep colonies are brown and spheric. 

 The growth pn agar-agar is similar to that of the colon bacillus. The organism 

 produces no indol, coagulates milk in a few days, and reduces litmus. It ferments 

 dextrose, mannite, dulcite and sorbite with the production of acid and the evolu- 

 tion of gas. It does not ferment saccharose, adonite, inosite or inulin. Upon 

 potato it forms a yellowish-white, shining layer. 



Pathogenesis. — The bacillus is pathogenic for mice, guinea-pigs, pigeons, 

 lambs, and kids, but not for dogs, cats, rats, or sparrows. The infection may be 

 fatal for mice and guinea-pigs, whether given subcutaneously, intraperitoneally, 

 or by the mouth. 



Lesions. — The bacilli are found scattered throughout the organs in small 

 groups, resembling those of the typhoid bacillus. 



At the autopsy a marked enteritis and swelling of the lymphatic follicles and 

 patches, with occasional hemorrhages, are found. The bacilli occur in the intes- 

 tinal contents. The spleen is somewhat enlarged. 



The bacillus is differentiated from the colon bacillus chiefly by its inability 

 to ferment lactose and saccharose, by the absence of indol-production, by its 



* " Archiv. de med. Experimentale," 1892, iv, p. 85. 



t "Korrespond. d. allg. arztl. Ver. von Thiiring," 1888, 9. " 



