682 Bacillus Icteroides 



BACILLUS ICTEROIDES (SANARELU). 



General Characteristics. An actively motile, flagellated, non- 

 sporogenous, non-liquefying, non-chromogenic, aerogenic, aerobic and 

 optionally anaerobic, pathogenic bacillus which stains by the ordinary 

 method, but not by Gram's method. It produces indol, but does not 

 coagulate milk. 



Sanarelli regarded this bacillus as the specific organism of 

 yellow fever. He found it in n autopsies upon yellow 

 fever cases, but always in association with streptococci, 

 colon bacilli, proteus, and other organisms. It is found in 

 the blood and tissues, and not in the gastro-intestinal tract, 

 and isolation of the organism was possible in only 58 per 

 cent, of the cases, and only in rare instances was accom- 

 plished during life. 



Distribution. By suitable methods it can be found in 

 the organs of yellow fever cadavers, usually aggregated in 

 small groups, in the capillaries of the liver, kidneys, and 

 other organs. The best method of demonstration is to 

 keep a fragment of liver, obtained from a body soon after 

 death, in the incubator at 37 C. for twelve hours, and 

 allow the bacteria to multiply in the tissue before exam- 

 ination. 



Morphology. The bacillus presents nothing morpho- 

 logically characteristic. It is a small pleomorphous bacillus 

 with rounded ends, usually joined in pairs. It is 2 104 ^ in 

 length, and, as a rule, two or three times longer than broad. 

 It is actively motile and has flagella. It does not form spores. 



Staining. It stains by the usual methods, but not by 

 Gram's method. 



Cultivation. The bacillus can be grown upon the usual 

 media. It grows readily at ordinary room temperatures, 

 but best at 37 C. 



Colonies. Upon gelatin plates it forms rounded, trans- 

 parent, granular colonies, which during the first three or 

 four days somewhat resemble leukocytes. The granular 

 appearance becomes continuously more marked, and usu- 

 ally an opaque central or peripheral nucleus is seen. In 

 time the entire colony becomes opaque, but does not liquefy 

 gelatin. 



Gelatin. Stroke cultures on obliquely solidified gelatin 

 show brilliant, opaque, white colonies resembling drops of 

 milk. The medium is not liquefied. 



Bouillon. In bouillon it develops slowly, without either 

 pellicle or flocculi. 



