BOTULISM. 247 



forms. The organism is strictly anaerobic, so that, in order to 

 cultivate it, anaerobic methods of investigation must be pursued. 

 The culture-media must always be distinctly alkaline, and the 

 growth is favored by the addition of two per cent, of grape- 

 sugar. 



Gelatin-plates exhibit between the fourth and the sixth day 

 round, transparent, brownish-yellow colonies, composed of 

 thick, glistening granules, in constant movement. The colonies 

 are surrounded by a slight zone of liquefaction. Later, the 

 margin becomes irregularly radiate, and, finally, processes of 

 the most varied form extend out from it. 



High gelatin stab-cultures exhibit no peculiarity. Round, 

 whitish masses develop along the line of puncture, at times 

 sending processes out into the adjacent gelatin. The gelatin is 

 not liquefied, but active gas-formation takes place. 



In agar stab-culture the growth, apart from liquefaction, is 

 quite similar. 



Glucose-bouillon is rendered deeply turbid. 



In milk slight development takes place, without alteration in 

 the nutrient medium. 



On potato no growth takes place. 



All of the cultures emit an odor of butyric acid. In addition 

 the bacillus generates in nutrient media containing glucose still 

 other fatty acids, butyl alcohol, hydrogen, carbon dioxid, and 

 methane. 



Tenacity of the Bacillus Botulinus. The cultures 

 retain their capability of development for more than a year 

 if they are kept at a temperature below 30 C. (86 F.). 

 At temperatures above 35 C. (95 F.) they die in the 

 course of a few weeks. The spores possess relatively little 

 resistance. They are destroyed at a temperature approxi- 

 mating 85 C. (185 F.) within a quarter of an hour, and 

 at a temperature of 80 C. (176 F.) with certainty within 

 an hour. Five per cent, carbolic acid causes their destruc- 

 tion in less than twenty-four hours. Dry spores exposed to 

 diffuse daylight exhibit capability of germination after three 

 months. The growing forms in emulsion with distilled 

 water die under these conditions within three or four 

 weeks. 



Pathogenic Properties. The bacillus botulinus proves 

 pathogenic when fed to guinea-pigs, mice, and monkeys. 

 One or two drops of a liquefied gelatin-culture placed upon a 

 bit of bread or in milk suffice to cause the death of the 

 animal within one or two days, after paretic manifestations, 



