SYMPTOMATIC ANTHRAX. 171 



Bacillus Botulinus. 



History. Yon Ermengen in 1896 discovered the Bacillus 

 botulinus (botulinus, a sausage) as the cause of an outbreak 

 of meat poisoning. He recovered the bacilli from fatal cases 

 of sickness produced by eating infected ham, finding the bacilli 

 in the stomachs and spleens. He also recovered similar bacilli 

 from the remains of the infected ham. 



Morphology and Staining. This bacillus is from 4 to 6 //. in 

 length and from 0.9 to 1.2 /j. in width. It has rounded ends 

 and occurs either singly or in small chains. It is flagellated 

 and slightly motile. In certain cultures spores are formed, 

 especially at low temperatures (20 C.). 



Biologic Characters. Bacillus botulinus is an obligate anae- 

 robe, growing best at a temperature below 37.5 C. and above 

 20 C., the optimum temperature being 25 C. It grows on 

 all culture-media, provided the reaction be neutral or slightly 

 alkaline. Gas is formed in the cultures. Milk is not coagu- 

 lated. It grows best on gelatine, which is liquefied. In the 

 liquefied zone surrounding the colonies the constant motion 

 of the growth may be noticed, and this is regarded by von 

 Ermengen as characteristic. In dextrose bouillon cloudiness 

 and gas are formed. 



Pathogenesis. The injection of meat, usually ham or sau- 

 sage or canned meat, infected with B. botulinus, gives rise to 

 symptoms after an incubation of about thirty-six hours.- The 

 symptoms are those of a profound intoxication, and most se- 

 vere in character ; strangely, vomiting and purging are rare. 

 Headache, chilliness without fever, trembling, and giddiness 

 are followed in severe cases by dilated pupils, loss of voice, 

 inability to swallow, and loss ot consciousness. In fatal cases 

 dyspnoea and general paralysis are the precursors of death. 



Laboratory animals are very susceptible, guinea-pigs, cats, 

 mice, and monkeys especially so. Rabbits are more resistant, 

 and birds even more so. The bacilli may be recovered from 

 the spleen after death. Lesions are those of a parenchymatous 

 degeneration of the organs, with general hypereinia and widely 

 distributed minute hemorrhages. 



