418 



INFECTION AND RESISTANCE 



EXPERIMENT II 23 



The materials used were Bacillus typhosus 65, typhoid-immune rabbit 

 serum (from rabbit A), 24 inactivated at 56 C., and fresh guinea-pig serum as 

 complement. The injected guinea pigs weighed from 150 to 225 grams. 



Similar in significance to the points just considered also is the 

 experiment of Friedberger and Szymanowski with Vibrio meichni- 

 Jcovi (confirmed by the writer with typhoid bacilli) that, although 

 sensitized and unsensitized bacteria will yield anaphylatoxin with 

 almost equal intensity, the poisons are produced from the sensitized 

 bacteria with far greater speed than from the latter. The difference 

 between the two, in fact, is probably one of degree only, since in ex- 

 periments without the addition of specific antiserum the bacteria 

 are nevertheless slightly sensitized by the normal antibody present in 

 the guinea-pig serum. 



That the production of the poison can under no circumstances be 

 regarded merely as a giving up from the bacterial cell of preformed 

 endotoxins under the influence of lytic substances which produce 

 greater permeability of the cell membrane was shown by STeufeld 

 and Bold, who extracted bacteria with lecithin salt solution and pure 

 salt solution, and from these extracts (but moderately toxic in them- 

 selves) produced typical anaphylatoxins by the action of complement. 

 The matrix of the poison thus is shown by direct experiment to be a 

 soluble ingredient of the bacterial cell. 



It was further shown by Friedberger and Nathan that the con- 

 ditions prevailing in the test tube experiment in truth represent the 

 processes taking place within the animal body. This they accom- 

 plished by injected bacterial emulsions into the peritoneal cavities of 



23 Zinsser. Loc. cit. 



24 This serum had an agglutinating titre of 1 :8,000 for Bacillus 

 typhosus 65. 



