BACTERIACE^E : THE SPOROGENIC ANAEROBES 277 



distributed in the soil and is commonly present in milk and other 

 animal food products. The cell is a large rod surrounded by_a 

 capsule when grown on media rich in protein or in the animal 

 body. The width of the cell (without capsule) varies 1 from i.i to 

 i.fu with a mean of 1.3^ and the length from 2.6 to 7.6/1, with an 

 average of 4.6/z, the measurements being made on organisms 

 grown in an agar stab-culture 24 hours at 37 C. When grown 

 in blood broth the germ is capsulated and the measurements, in- 

 cluding the capsule are as follows: width 1.9 to 2.5/1 with average 

 of 2.i;u, and length, 2.8 to 6. 6 /* with average of 4.7/11. Usually the 

 organism is non-motile, but flagella can sometimes be demon- 

 strated. In the intestine and in protein media the organism 

 forms spores, usually median without bulging of the cell, but 

 these are not commonly observed in cultures. The organism is 

 a strict anaerobe. Its most striking property is the enormously 

 rapid production of gas in media containing dextrose or lactose. 

 Cultures are obtained most readily by heating a suspension of 

 feces to 80 C. for 15 minutes and inoculating it into glucose broth 

 mixed with blood in a Smith fermentation tube. After 24 to 48 

 hours incubation its presence will usually be revealed by abun- 

 dant production of gas. Milk is coagulated and rendered acid 

 with an abundant production of gas (stormy fermentation). 

 On blood-agar plates incubated in hydrogen, the colony is round 

 with regular outline and surrounded by a clear zone of hemolysis. 



Emphysematous gangrene occurs in man as a rapidly extend- 

 ing, very fatal disease, due to the infection of wounds with this 

 organism. The presence of necrotic tissue seems to be necessary 

 in order that the organism may gain a foothold, but when once 

 begun the inflammation may extend with great rapidity. The 

 gas found in bodies at autopsy is usually the result of an agonal 

 or a post-mortem invasion by the bacilli from the intestine. 



There are several other types of sporogenic anaerobes of the 

 same general nature as B. edematis, B. feseri, and B. welchii, iso- 



1 The measurements are taken from Kerr, The Bacillus welchii, Thesis, Univ. 

 of Illinois, 1909. 



