18 HILDA HEMPL HELLER 



Genus 10. Welchillus nov. gen. 



Clostridioideae that liquefy gelatin but do not produce hydro- 

 gen sulfid demonstrable by lead-acetate-paper test in blood- 

 broth. They produce much acid and gas on meat medium, 

 but they do not digest it, nor do they digest casein, coagulated 

 serum, or eggvvhite. They produce stormy fermentation of 

 milk and attack many sugars vigorously. Their multiplica- 

 tion is extraordinarily rapid ; they are killed by their own growth 

 products in acid media, in which they fail to sporulate. Deeply 

 Gram-positive non-flageUate rods with square ends. They 

 produce oval subterminal or median spores in alkaUne media, 

 or in media free of fermentable carbohydrate; these spores do 

 not bulge the sides of the baciUi. When growing rapidly the 

 rods are very short, and resemble closely no other type here 

 listed except Stoddardillus. When growing slowly the rods are 

 less abundant and longer, and may be mistaken for MarteU 

 lillus and similar organisms. Typically intestinal saprophytes ; 

 ubiquitous. JNIany strains produce toxin and invade tissue, 

 forming gas, and causing the formation of oedema, and in many 

 cases causing the disintegration of muscle and of connective 

 tissue without the production of a foul odor. This disintegra- 

 tion occurs only in vivo, and is probably due to the enzymes 

 of the host tissue. Welchillus are the most frequent anaerobic 

 invaders noted on the hospital autopsy table: the organisms 

 are present in human intestines. Causative agents of a probably 

 greatly overestunated percentage of gas gangrene cases follow- 

 ing war wounds. Comparatively rare as animal invaders. 



Type species W. aerogenes (Bacillus aerogenes-capsulatus 

 Welch and NuttaU) type I as defined by Sinionds (type TV of 

 Esty). Ferments, besides other carbohydrates, inuhn and 

 glycerol. Usually pathogenic for guinea-pigs. 



Synonyms. B. phlegmones-em-physematoseae Fraenkel, B. 

 perfringens Veillon and Zuber, 'Bacille de reumatisme aigue' 

 of Achalme, Butyribacillus immobilis-liquefaciens Grassberger 

 and Schattenfroh. Descriptions and discussions, most of them 

 with large bibliographies, are to be found under the names of 

 the following authors: von Hibler, Simonds, Robertson, Wein- 



