SPORE-FORMING PATHOGENIC ORGANISMS 85 



formed by this organism, and the intoxication is due to 

 its formation in meat before ingestion. The toxin is 

 destroyed by exposure to 80 C. for half an hour, and 

 food causing the outbreaks has been either raw or im- 

 perfectly cooked. As growth of the bacillus is checked 

 by a 6 per cent, solution of salt, van Ermengem has 

 recommended that in salting a brine containing at least 

 15 per cent, of sodium chloride should be used. 



The disease is now rare on the Continent, and Savage 

 was unable to trace the occurrence of a single outbreak 

 in this country. 



An antitoxin prepared by Kempner is said to be of 

 value even some hours after ingestion of infected food. 



Bacillus Welchii. 



An organism commonly found in emphysematous gan- 

 grene was discovered by Welch and Nuttall (1892), and 

 named B. aerogenes capsulatus. Frankel (1893) inde- 

 pendently described B. plilegmones emphysematosce, which 

 is identical with Welch and Nuttall' s organism. Klein 

 attributed an outbreak of diarrhoea in St. Bartholomew's 

 Hospital (1895) to an organism (B. enteritidis sporogenes) 

 found by him in the dejecta of patients. Oftentimes, 

 regardless of all the attributes of Klein's bacillus, this 

 name is commonly applied to a normal inhabitant of the 

 digestive tract which is described here as B. Welchii. 

 Other observers have independently discovered organisms 

 either identical or very similar. Chester has renamed this 

 organism, or class of organisms, B. Welchii. 



Morphology. . Welchii is a plump, long bacillus 

 (3^ to 6/i long), with almost square ends, occurring singly, 

 in chains, and in clumps. The length varies greatly on 

 culture, when different media are used. It frequently has 

 a capsule, and forms oval spores, generally situated near 

 one end, but only in serum cultures. It is strictly anaero- 

 bic, is Gram-positive and non-motile. B. enteritidis 

 sporogenes is described by Klein as multi-flagellate and 

 motile, and as sporing in gelatin. 



Cultural Characters. Gelatin is slowly liquefied. Gas 

 (two-thirds or three-quarters of which is hydrogen) is 

 produced in dextrose, lactose, and saccharose media. 

 Since its growth is not suppressed by bile-salt it gives a 

 po bitive reaction in MacConkey's bile-salt media like the 



