118 INFECTION 



grows at room temperature and causes marked gas formation in glucose 

 media. 



The toxin is readily produced in anaerobic alkaline bouillon cultures. 

 It is quite labile. 



Symptoms of botulism appear only after a definite period of incuba- 

 tion, which varies from twenty-four to forty-eight hours. In contra- 

 distinction to the meat poisonings produced by other organisms,* those 

 due to Bacillus botulinus may show few or no symptoms directly re- 

 ferable to the intestinal tract, the chief symptoms being due to toxic 

 interference with the cranial nerves: loss of accommodation, ptosis, 

 dilated pupils, aphonia, dysphagia, and hypersecretion of mucus from 

 the mouth and nose. 



Guinea-pigs are quite susceptible, and may be infected by way of the 

 mouth. The symptoms of intoxication usually follow in twenty-four 

 hours, and are characterized by motor paralysis, dyspnea, and hyper- 

 secretion of mucus from the nose and mouth. 



4. Dysentery Toxin. The distinct types of dysentery bacilli vary 

 exceedingly in their powers to produce toxins, the strongest poisons 

 being produced with bacilli of the Shiga-Kruse variety, less regularly 

 active ones, with bacilli of the Flexner type. 



Investigations have shown quite conclusively that dysentery itself 

 is a true toxemia, its symptoms being referable to the absorption of the 

 toxins of the bacillus from the intestine. Flexner, who has studied this 

 subject with great care, believes it probable that most of the pathologic 

 lesions occurring in the intestinal canal are referable to the excretion of 

 dysentery toxin, rather than to the direct local action of the bacilli. 

 The action of the dysentery toxin upon animals is very characteristic, 

 and throws much light upon the disease in man. Intravenous injection 

 of the toxin in rabbits is followed by marked diarrhea, rapid fall in tem- 

 perature, respiratory embarrassment, and terminal paralysis. Upon 

 autopsy the intestinal mucosa, especially that of the cecum and colon, 

 shows marked inflammatory involvement, supporting Flexner's ob- 

 servation of the necrotic action of excreted toxin. 



Dysentery bacilli also produce an endotoxin, and poisonous sub- 

 stances are easily obtained by extracting the bacilli themselves or by 

 filtration of properly prepared bouillon cultures. The toxin is fairly 

 stable, and well preserved under toluol in the refrigerator. 



5. Staphylolysin. Two definite toxins have been isolated from 

 cultures of Staphylococcus pyogenes aureus and albus, one of which 



