262 MANUAL OF BACTERIOLOGY. 



easily decolorized by Gram's method; this may be doubted, 

 however. The organism has been cultivated. It is faculta- 

 tive anaerobic. It grows rapidly, best in the incubator. It 

 does not liquefy gelatin ; its growth in gelatin stick-cultures 

 resembles the bacillus of Friedlander. It grows on the 

 ordinary media. Gas may be developed upon potato. 



It is pathogenic for mice and guinea-pigs, less so for 

 rabbits. Its virulence is less than that of Friedlander's 

 bacillus. 



It has been obtained from the tissues of cases of rhino- 

 scleroma. Rhinoscleroma is a disease characterized by a 

 chronic tubercular thickening and swelling of the skin 

 around the nose and similar swelling of the nasal mucous 

 membrane, sometimes followed by ulceration. It is com- 

 monest in Austria and Italy. It has been seen in America 

 only with the greatest rarity. 



The organisms may be stained in the diseased tissues, 

 but their detection is a matter of considerable difficulty, 

 and they are not always found. It is not yet certain that 

 they are the cause of rhinoscleroma. 



Bacillus pyocyaneus. A slim bacillus with rounded 

 ends. It is motile. It does not form spores. At 56 C. 

 it is killed in ten minutes. It is decolorized by Gram's 

 method. It is aerobic; grows well at ordinary tempera- 

 tures; liquefies gelatin, and grows on the ordinary culture- 

 media. Cultures present a blue or green color, especially 

 in transparent media. This color is not confined to the 

 growth itself, but a blue or green fluorescence spreads 

 over the whole medium. In old agar-cultures the color 

 may become very dark. The pigment forms in the pres- 

 ence of oxygen, and is due, at least in part, to the pto- 

 maine, pyocyanin. On potato the growth is usually brown, 

 which may be tinged with green. Milk is coagulated and 

 peptonized and an acid reaction is developed. Indol is 



