BACILLUS ULNA 239 



coloured ; in thrust-cultures the growth is granular, owing 

 to the close apposition of the punctiform colonies, and on 

 agar there is an abundant superficial growth. 



The Bacillus salivarius septicus shows short rods with 

 pointed ends which at times lie in chains, at others in clumps, 

 and grow best when a little phosphoric or hydrochloric 

 acid (0*04 per cent.) is added to the medium. Gelatine is 

 not liquefied. Eound colonies with a transparent periphery 

 develop on the plate, and the islets show a zigzag network 

 under a high power. A thrust-culture appears as a clear 

 band with peripheral dots. If a transmission be made to 

 agar from a gelatine culture, a transparent coating develops. 



Both have a pathogenic action upon mice, guinea-pigs, 

 and rabbits, and the animals die of septicaemia, sometimes 

 in as short a time as forty hours. 



Bacillus ulna. Vignal found in the mucus from his 

 mouth rods with rounded ends, which liquefy gelatine in 

 growing. The colonies are round, and appear on the plate 

 like two concentrically- arranged stripes separated by a clear 

 line. Several zones appear in the liquefied part and towards 

 the border, the outer one of which looks like a tangle of 

 fine fibres. In thrust-cultures a funnel-shaped area of 

 liquefaction appears along the needle-track, on the bottom 

 of which lie crumbling accumulations of bacteria, and in a 

 few days a shining membrane forms on the surface. Growth 

 progresses best at 20 C. On agar there appears at incuba- 

 tion temperature a deposit in the form of a coherent pellicle, 

 which can with difficulty be raised from the surface of the 

 medium. A coating develops on potato at the same tem- 

 perature. Serum is liquefied. The smell of the cultures 

 resembles that of decomposed pus. 



Bacillus gingivae. Miller isolated thick rods with 

 rounded ends from the deposit in a mouth not kept properly 

 clean, and in the suppurating pulp of a tooth. They form 



