454 BACILLUS CEDEMATIENS 



blood after death. Intramuscular or subcutaneous injection in 

 the guinea-pig gives a similar picture, the chief feature being the 

 extent and thickness of the oedema ; the lesion has no putrid 

 odour. The organism has been shown by Weinberg to form a 

 soluble toxin, which in the case of some strains is very active. 

 Injection of a filtrate from a fluid culture reproduces the 

 characteristic oedema in the guinea-pig. He has also produced 

 an antitoxin which is efficient when tested experimentally, and 

 which has been used in some cases of the human infection, 

 apparently with success. 



Bacillus tertius. — This is another saccharolytic bacillus, but with 

 terminal spores. It is common in contaminated wounds, and the name 

 was given by Henry, as he found it to be third in order of frequency 

 among the anaerobes. It is regarded as being probably the same as the 

 bacillus IX of von Hibler and the bacillus Y of Fleming. The b. tertius is 

 a fairly long and thin bacillus, and is often somewhat curved ; it is Gram- 

 positive, but the power of retaining the stain is soon lost in cultures. It 

 is feebly motile or non-motile. Thelspores are terminal ; the small forms 

 are round, and stain deeply with a basic dye ; the larger are oval, racquet- 

 shaped, sometimes of considerable length, and give the ordinary staining 

 reactions of spores. Occasionally a spore is present at either end of a 

 bacillus. The superficial colonies are round, semi-transparent discs, which 

 do not become large ; the deep colonies are of lenticular shape ; occasion- 

 ally, from both, small offshoots occur. On a moist surface there is a 

 tendency for the growth to spread as a thin film. In milk a small 

 amount of gas is produced, and a day or two later a soft friable coagulum. 

 In cooked meat medium both acid and gas are formed ; later the fluid 

 becomes clear and the meat assumes a pink colour. There is no liquefac- 

 tion of gelatine or coagulated serum. The organism has wide fermenta- 

 tive action when tested on various carbohydrates, but different strains 

 vary in this respect. It has practically no pathogenic effects when tested 

 experimentally, though it probably gives rise to gas-formation in wounds 



The three following organisms are examples of the proteolytic 

 group : — 



Bacillus sporogenes. — This organism, which was first separated from 

 feces by Metchnikoff and described by him, is probably the commonest 

 anaerobe in cultivated soil. • It is present in the great majority of putrid 

 wounds, and owing to its rapid growth and spore formation, often inter- 

 feres with the separation of other anaerobes. It is a fairly large bacillus, 

 of about the same length as the b. welchii, but thinner, and usually occurs 

 as single elements. It is Gram-positive, but as is common with members 

 of the group, Gram-negative forms are to be found in older cultures. 

 Spore-bearing forms are common in wounds, and in cultures spores are 

 formed with great rapidity, so that they may be seen within twenty-four 

 hours. The spores, which have very high powers of resistance, are usually 

 subterminal, though occasionally central in position. The organism 

 possesses numerous lateral fiagella, and most strains are actively motile. 

 It grows readily under anaerobic conditions, and the cultures have a 

 markedly putrid odour. In deep glucose-agar tubes the growth forms a 



