so 



ROBERT GRAHAM AND HERMAN R. SCHWARZE 



IMMUNOLOGICAL FINDINGS 



Ininiunological tests upon guinea-pigs using unfiltered broth 

 cultures of the toxic anaerobe isolated from corn silage (126) 

 and botulinus antitoxin prepared from a heterologous strain of 

 B. botulinus, gave evidence of the identity of the toxin and 

 according to Burke's classification (1919) proved to be of type B 

 variety. The strain possesses the usual pathogenic characters 

 for small laboratory animals and is culturally analagous to 



Fig. 4. Immunologic Test Showing Relation of Strain of Toxin from 

 Silage No. 126, B. botulinus Antitoxin (Type B) 

 The three pigs in the rear received the serum and toxin. The control pig 

 received the toxin only. 



other strains of B. botulinus. Botulinus antitoxin (type B) 

 proved efficacious in small animals against many lethal doses 

 (c. f. 100) of toxin per os. An arbitrary toxic unit of 0.001 cc, 

 which represents the minimum lethal dose, when given per os to 

 guinea pigs of a given weight, has been tentatively used in deter- 

 mining the relative potency of antitoxic serum. This toxic 

 unit per os in guinea-pigs weighing 250 grams may produce 

 symptoms in twenty-four to forty-eight hours and is invariably 



