PROTEIN POISONS 



guinea-pigs, and found that animals sensitized to a serum, 

 and given a non-fatal reinjectiori of the homologous serum, 

 after recovery survived the; minimum fat.nl dose of anaphyl- 

 atoxin. From these experiments H< -an reached the 

 following eonelusions: (\) The condition or state of anti- 

 ana phyla xis i , not pecific. (2) It is not. due to absorption 

 of the ferment ("antibody;. (X) It is due to increased toler- 

 ance of, or lessened 'susceptibility to, the poison. FrJcdbergcr 

 and his students' have taken up these points, and by exact, 

 quantitative experiments have demonstrated that the 

 State of anti-anaphylaxis, like that of anaphylaxis, is 

 strictly specific, but that it is true that increased tolerance 

 doc, play a part in the experiments as made by Bessau. 

 When an animal is simultaneously sensit.i/ed to two sera, 

 and after the condition of sensitizat.ion has been fully 

 developed, a non-fatal reinjcct.ion of one of the < 

 renders the animal after recovery absolutely insusceptible 

 to any dose of the serum which has been employed in the 

 reinfection, but leaves it still susceptible to the second serum 

 in doses only slightly larger than those required to kill 

 control animals .:ensili/ed to that serum only. We can 

 make this plainer by the following statement. When an 

 animal is seiis.it ized to two sera, two specific proteolytic 

 ferment., arc developed. When an animal in full sensiti/a- 

 t.ion to both sera is treated with a non-lethal reinjection of 

 one of them, the specific ferment for this scrum is exhausted, 

 and a certain amount of the poison is set free, not enough 

 to kill the animal, but enough to give the animal increased 

 tolerance to the poison. ( 'onscqiient ly the fatal dose of the 

 other serum Qi to kill on reinjection, say, twenty-four 



hour, later, i., larger than the minimum fatal dose when the 

 animal ha b< i izcd to only one serum. We demon- 



strated (seepage lo!);ma.n\ yean ago not only that tolerance 



to the protein poison can be increased, but that resistance 

 to living cultures of pathogenic bacteria may be incrca ed 

 by repeated doc, <,f the poi on. Furthermore, we .showed 



i ch, i. liniiiuii, .;7i . 



