F. FRAOILIS 483 



fusiform organisms fermented only glucose and sucrose, were indole + , and HjS + in the 

 absence of cysteine ; Group II organisms fermented glucose, sucrose, maltose, trehalose, 

 lactose and raffinose, were indole negative and H2S + only in the presence of cysteine. 

 The place of F. fusiformis in these groups is not clear but it is more nearly related to 

 Group II and to the Type IV of Slanetz and Rettger. Hine and Berry (1937) could find 

 no such clear-cut association between fermentation reactions and cultural characters. 

 The organisms do not form spores. They are killed in 15 minutes by moist heat at 

 55° C, but resist 1 per cent, antiformin for 5 minutes. In cultures they may remain 

 alive for 6 to 8 weeks. Injections subcutaneously or intramuscularly into rabbits and 

 guinea-pigs may have little or no effect ; at most an abscess is produced ( EUermann 

 1905). 



F. ramosus. — Said by VeiUon and Zuber (1898) to be one of the commonest organisms in 

 appendicitis ; has also be«n reported in human gas gangrene and bactersemia (Lemierre, 

 ReiUy and Bloch-Michel 1937). Gram-positive, non-motile, non-sporing rod, sUghtly 

 larger than Erysipelothrix rhusiopathice ; arranged in pairs or short chains ; in pus it is 

 rather short but in culture it may form pseudo-filaments, which are really made up of 

 numerous short rods. V-forms and Y-forms are common. No growth occurs at room 

 temperature ; and at 37° C. colonies do not become visible for 3 or 4 days. Surface 

 colonies on agar are very fine, effuse, greyish-white, and translucent ; later, they become 

 granular and shghtly cloudy. Deep colonies in agar are very small greyish pomts, which 

 under low magnification are seen to be ovoid and granular with hatched borders ; as 

 the colony grows, it becomes greyish-yellow, and the edges become more defined. In 

 broth it produces a uniform tiu-bidity in 3 or 4 days with a greyish-white muddy deposit. 

 Cultures have a characteristic oetid odour, but very little gas is formed. Strict anaerobe. 

 Acid is formed in glucose, galactose and mamiitol, and sometimes in lactose, saccharose 

 and maltose. Lactose-fermenting strains clot Htmus milk. Indole — . Gelatin not hquefied 

 (Weinberg et al. 1937). Cultures five for over a month. Inoculated intravenously into 

 rabbits, it causes death in some days by intoxication and cachexia. Subcutaneous in- 

 occulation into raljbits causes abscess formation with death in 8 to 10 days. 



F. serpens. — Isolated by VeiUon and Zuber (1898) from the pus of a mastoiditis in 

 a child who died of pulmonary gangrene. Large, slightly motile. Gram-negative rod with 

 rounded ends, arranged in pairs end-to-end, or in pseudo-filaments. Strict anaerobe. 

 Grows best at 37° C, but develops at 20° C. Surface colonies on agar after 48 hours 

 are only just visible ; later they form small cloudy translucent masses of greyish colour. 

 Deep colonies in agar after 24 hours at 37° C. are small, clear, rounded, greyish, granular 

 masses with hatched edges, and sometimes a bouquet of filaments at one point on the 

 periphery ; later they increase in opacity and the edges become better defined. In gelatin 

 stab there is a filiform growth ; liquefaction occurs down the whole length of the stab ; 

 the liquefied gelatin remains clear, and flocculi of growth fall slowly to the bottom forming 

 a white deposit. Deep colonies in gelatin are round, greyish, and liquefy the gelatin slowly. 

 In broth there is a rapid turbidity, followed by a clearing of the medium with the forma- 

 tion of a white deposit. Acid and gas are formed from glucose, Isevulose, maltose, galactose 

 and lactose. Indole — . No haemolysin. Cultures have a foetid odovu", but only a small 

 amount of gas is evolved. Cultures remain viable for about 20 to 25 days. Pathogenic 

 for mice, guinea-pigs, and especially rabbits, but not so pathogenic as F. ramosus. 



F. fragilis. — Said by VeiUon and Zuber (1898) to be the commonest organism in appen- 

 dicitis. Non-motUe, Gram-negative, rod with rounded ends, sUghtly smaller than the 

 diphtheria bacillus ; axis straight or slightly curved ; arranged singly or in pairs end- 

 to-end. Strict anaerobe. Difficult to isolate. Surface colonies on agar are extremely 

 fine, greyish, and translucent, and tend to undergo autolysis in a few days. Deep colonies 

 in agar do not become visible for 3 or 4 days ; they are very small, round, irregularly 

 round, or ovoid, brownish-yeUow, opaque, with an entire edge. Deep colonies in gelatin 

 appear in 8 to 10 days ; they are punctiform, yeUow, granular, with an entire edge ; no 



