BACTERIAL CELLULAR SUBSTANCE 49 



The relative toxicity of the finely powdered cellular sub- 

 stances of certain bacteria in proportion to body weight of 

 animal, is shown in the following figures : 



Bacillus anthracis 1 to 1,700 



Sarcina lutea to 2,050 



Micrococcus pneumonise . ( . . . . ". . to 10,000 



Sarcina aurantiaca . ... . . , ." . . . to 25,500 



Bacillus violaceus . to 26,500 



Bacillus diphtherise . . . . ". . ., . to 33,000 



Bacillus typhosus .to 40.000 



Bacillus pyocyaneus to 50,000 



Bacillus coli . to 75,000 



Bacillus prodigiosus to 90,000 



Numerous and varied attempts to immunize animals 

 with the bacterial substances were made. Guinea-pigs, 

 rabbits, and goats were used in these experiments. The 

 following quotation is taken from the report Marshall and 

 Gelston 1 made in 1902: 



"1. Although guinea-pigs and rabbits acquire immunity 

 to the germ substance but slowly, yet if sufficient time be 

 given, and the animal be allowed to recover before a second 

 dose is administered, a fair degree of immunity may be 

 obtained after many months of treatment. Unless the 

 animal be allowed to recover completely before a second 

 injection is given, death generally results. In these ex- 

 periments for the purpose of inducing immunity, we 

 employed the finely divided germ substance which had 

 been used in determining the toxicity. Our previous 

 experiments had shown that one part of the finely divided 

 powder to 75,000 parts of body weight in a guinea-pig 

 was surely fatal. Guinea-pig No. 93 received in the fifteenth 

 injection a dose of 28 mg. (1 to 17,321), and recovered from 

 the same. Guinea-pig No. 109 received on the ninth injec- 

 tion 25.5 mg. (1 to 22,745), and recovered. Rabbit No. 17 

 received on the fifteenth injection 372.3 mg. (1 to 4780), 

 and recovered. Rabbit No. 29 received on the thirteenth 

 injection 293.3 mg. (1 to 6409), and recovered. 



1 Loc. cit. 



