164 A MANUAL OF BACTERIOLOGY 



was isolated from the false membrane of the 

 diphtheria of pigeons. It is a short rod with 

 rounded ends, and occurs in irregular masses. On 

 the surface of gelatine, it forms light yellow films, 

 while in the deeper layers of that medium white 

 nodules are formed. This bacillus destroys pigeons, 

 sparrows, mice, and rabbits ; but fowls, guinea-pigs, 

 rats, and dogs have an immunity. 



Bacillus of Diphtheria of Rabbits. This microbe 

 measures 3 to 4 yu, X 1 /-t ; it has rounded ends, and 

 occurs singly, in pairs, or in long chains. On 

 gelatine-plates it forms grey colonies, which become 

 brown. It was isolated during growth in 'the 

 diphtheritic processes of the intestine ; ' and causes 

 (in rabbits) an inflammatory exudation in the 

 alimentary canal. 



Bacillus cavicida. This microbe was discovered, 

 by Dr. Brieger, in faeces and putrefying fluids. The 

 rods are very small, and they form colonies com- 

 posed of white concentric rings on gelatine plates. On 

 potatoes they give rise to dirty yellow masses. They 

 are fatal to guinea-pigs, but not to mice and rabbits. 



Bacillus pyogenes fatidus. A microbe with 

 rounded ends, and measuring 1*45 X 0'58 //,, was 

 isolated from putrid pus. It occurs in pairs or 

 chains, and is motile and produces spores. On the 

 surface of gelatine and agar-agar it forms greyish 

 films, and on potatoes a shining brown growth is 

 developed. From all these media a strong putrid 

 odour emanates, but no smell is given off when the 

 microbe is cultivated in milk. It is fatal to mice 

 and guinea-pigs. 



