BACILLUS BUTYRI VISCOSUS 183 



bell into which hydrogen is conducted in the presence of 

 pyrogallol, the apparatus being luted with paraffin. The 

 same observer recommends sugar-agar as a nutrient medium. 

 After continuing in the incubator for two days, the colonies 

 have made such progress that they can easily be trans- 

 planted as pure growths to high cultures in agar. Round 

 colonies form, which give the impression of a felt consisting 

 of closely-intertwined filaments, and are provided with a 

 considerable number of processes radiating out from all 

 sides. Gelatine is very rapidly liquefied. On potato 

 there develops at the depth of a millimeter an abundant 

 growth of bacilli, which loosen the substance of the medium 

 to a marked degree, and exhale a peculiar odour resem- 

 bling that of alcohol. 



Bacillus butyri viscosus. Lafar constantly found short 

 rods in butter, having rounded ends and not seldom 

 forming chains. Thrust-cultures spread but little over the 

 surface of the gelatine, but along the needle-track there 

 occur figures resembling the scales of fish, in lumps, or often 

 in clusters, and which do not liquefy the medium. Small 

 white dots appear on the surface of the gelatine plate, which 

 grow decidedly more in height than in width, gradually melt 

 into the form of small lenticular discs, and cover the whole 

 of the gelatine, which remains solid, with a slimy film about 

 half a millimeter in thickness. On potato a fine moist 

 shining layer develops, resembling that formed by typhoid 

 bacilli. Growth takes place whether air is excluded or 

 present. 



The Bacillus butyri fluorescens, isolated from butter by 

 Lafar, seems to be identical with the Bacillus melochloros 

 obtained from air by F. Winkler and Von Schr otter in the 

 author's Institute. (See p. 118.) 



Spirillum tyrogenum. Deneke cultivated from old cheese 

 a variety of comma-bacillus which has strongly curved 



