484 FUSIFORMIS 



liquefaction. Uniform turbidity in broth with a whitish deposit. Cultures have a foetid 

 odour, but evolve little gas. Cultures in agar remain viable for less than a week. Sub- 

 cutaneous inoculation into guinea-pigs produces abscess formation. The organism is 

 more pathogenic for the rabbit, producing on subcutaneous inoculation an extensive 

 phlegmon with sloughing of the skin, and death in 6 to 7 days. Intravenous inoculation 

 of the rabbit is followed by death, but no organisms can be found in the tissues at 

 necropsy ; probably death is due to toxaemia, for the same result is brought about by 

 killed cultures. 



F. furcosus. — Not so common in appendicitis as F. fragilis and F. ramosus. In pus 

 it is a very small rod, with one of its ends forming two little branches like a Y. In cul- 

 ture it forms rods ; many of these increase in length, and divide at one of their extremities 

 into two branches, each terminated by a swelling ; others form branches, which them- 

 selves divide. The bacilli and their branches are never very long ; the swellings are rounded 

 or pyriform, and are numerous. The whole organism is slightly larger than the tubercle 

 bacillus. Non-motile and Gram-negative. Strict anaerobe. No growth at room tem- 

 perature ; at 37° C. growth is not visible for 3 or 4 days. Surface colonies on agar are 

 very fine grey points, scarcely raised at all from the medium ; under low magnification 

 they appear yellowish, very finely granular, and have transparent borders. Deep colonies 

 in agar are so small and transparent that they are dilBcult to see ; when magnified, they 

 are round and yellowish, with delicate regular borders. A fine precipitate is formed in 

 broth. Cultures have a slightly foetid, sour odour, but evolve very little gas. Cultures 

 remain viable for 15 to 20 days. Subcutaneous inoculation into a guinea-pig produces 

 an abscess, which generally heals ; sometimes death occurs after several weeks from 

 cachexia. 



F. melaninogenicus : — Isolated by Oliver and Wherry (1921) from the mouth, infected 

 wounds, urine and faeces of the human subject. On haemoglobin-containing media it 

 forms a melanin-hke pigment. According to Burdon (1928) it is a small Gram-negative, 

 non-sporing diplococcobacUlus growing feebly on blood media unless mixed with other 

 organisms, when its growth is more profuse. The pigment develops slowly ; after 1-2 days 

 the colonies may be stained a pale brown ; in 4-5 days they are a deep black in colour. 

 Cultures have a foul odour. By the time pigmentation is fuUy developed, the culture 

 is often dead, which may account for the infrequency with which this organism has been 

 isolated and its pecuhar chromogenic character recognized. Weiss (1943) reported local 

 inflammatory oedema, followed by necrosis, after intradermal injection of young cultutes 

 in rabbits, but no effect after intraperitoneal injection in mice. 



Its pathogenicity is probably low. In man, it has been isolated from purulent lesions, 

 usually along with other pathogenic bacteria, and sometimes from the blood. 



REFERENCES 



Bachmann, W. and Gregor, H. (1936) Z. ImmunForsck., 87, 238. 



Beaver, D. C, Henthorne, J. C, and Macy, J. W. (1934) Arch. Path., 17, 493. 



Beveridge, W. I. B. (1934) J. Path. Bad., 38, 467. 



Burdon, K. L. (1928) J. infect. Dis., 42, 161. 



Castellani, a and Chalmers, A. J. (1920) " Manual of Tropical Medicine." 3rd Ed., 



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 Cohen, J. (1932) Arch. Surg., 24, 171. 



Dack, G. M. and Burrows, W. (1935) Proc. Soc. exp. Biol, N.Y., 32, 1441. 

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