BOTULISM 



401 



Dickson, for months or even years if protected from the action of 

 light and air, even though the medium in which they are immersed 

 is of acid reaction. The toxin which they produce is quickly de- 

 stroyed by exposure to the action of light and air, but will maintain 

 its virulence for six months or more if kept in the dark and sealed. 

 According to Van Ermengen, the toxicity is diminished by heating 

 at 56 C. for three hours and destroyed by heating to 80 C. for half 

 an hour or by boiling. Dickson found that the toxin may develop 

 in mediums such as green corn, artichokes, asparagus, apricots, and 

 peaches to which no traces of animal proteins have been added in 

 addition to the various meats. 



FIG. 48. Bacillus Botulinus. (After Dickson.) 



The pronounced symptoms which develop on the ingestion of the 

 toxin are thus described by Wilbur and Ophiils: 



" Girl, aged twenty-three, Tuesday evening, November 23, 1913, 

 ate the dinner including the canned stringbeans of the light green 

 color together with a little rare roast beef. The following day she 

 felt perfectly normal except that at 10:00 in the evening the eyes 

 felt strained after some sewing. Thursday morning, thirty-six 

 hours after the meal, when the patient awoke, the eyes were out of 

 focus, appetite was not food, and she felt very tired. At night she 

 had still no appetite, was nauseated, and vomited the noon meal 

 apparently undigested. Friday morning, two and one-half days 

 after the meal, the eyes were worse, objects being seen double on 

 quick movement, and it was noticed that they had a tendency to be 

 crossed. A peculiar mistiness of vision was also complained of. 

 She was in bed until late in the afternoon, when she visited Dr. 

 Black. She had had some disturbance in swallowing previous to 

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