394 SUMMARY OF CURRENT RESEARCHES RELATING TO 



displacement and cloudiness of the nucleus, and eventually complete 

 destruction of the cell. These changes occur in the medulla and cause 

 nuclear paralysis, and respiratory or cardiac stoppage. J. E. 



Bacteria of Gas Gangrene. — R. Pfeiffer and G. Bessau {Deutsche 

 med. We/inschr., 1917, 43, 1217, 1255, 12S1). The authors regard " ijas 

 gangrene " as due to the combined action of a variety of anaerobic 

 bacilli, and never as the result of a single variety. In 150 cases from 

 the Somme front, Fraenkel's bacillus, B. serogenes e neaps ulat us, was the 

 most common, but never alone. They emphasize the difficulty of 

 obtaining pure cultures of any of the anaerobes. 



They describe in detail four organisms only, two classified as " non- 

 putrefiers " and two as "putrefiers." 



Non-putrefying organisms : — 



1. Bacillus of Fraenkel (probably i?. serogenes encapsulatiis, B. ivekhii, 

 B. perfringens, of British writers), a plump, non-motile bacillus, does 

 not form spores in agar or broth even after a period of weeks. Very 

 scanty spores may be formed after a time on coagulated serum and in 

 meat-broth. 



2. Bacillus of Malignant (Edema (Koch) is longer and narrower 

 than Fraenkel's bacillus, and is very Gram-labile. Varies in motility. 

 SHght sporulation in agar and liver-broth, very abundant spores in a 

 meat-broth culture. On agar-plates the colonies develop very slowly, 

 and after tiiree days appear as very small, fine, slightly cloudy colonies 

 with finely branching filamentous margin. In old meat-broth cultures 

 many free spores may be found, and after a fortnight the meat in the 

 medium begins to dissolve. The cultures have a slightly rancid odour, 

 and there is no putrefaction. 



The putrefying organisms are the following : — 



1. The so-called " Uhrzeiger," or Clock-hand Bacillus. Very motile. 

 Gram-positive, and spores abundantly on all ordinary media. Abundant 

 gas is produced, and a very foul odour. Meat-broth and brain-broth are 

 both blackened. 



2. The " Par oedema Bacillus," morphologically similar to Koch's 

 bacillus of Malignant CEdema, but producing marked putridity in 

 culture. It is non-motile, forms spores in meat-broth, and the meat is 

 slowly dissolved. J. E. 



