PROTEIN SENSITIZATION OR ANAPHYLAXIS 245 



when the temperature reaches 130; at 135 to 140 it 

 becomes gelatinous and is no longer toxic when tested on 

 sensitized guinea-pigs. 



Symptoms. The symptoms induced by the reinjection 

 of a homologous or closely related protein into an anaphyl- 

 actized animal vary within certain limits in different species 

 of animal, but in the same species are constant, whatever 

 the protein used. This in itself is a strong argument in 

 favor of the claim made by us that the anaphylactic poison 

 is the same, in its physiological action at least, whatever 

 the protein be. In other words, it is strongly in favor of the 

 view that all proteins, at least all which possess the capa- 

 bility of sensitizing animals, contain the same poisonous 

 group and the symptoms are due to the liberation or 

 activation of this poison. 



When a sensitized guinea-pig receives a reinjection of 

 the same protein to which it has been sensitized after a 

 proper interval of time, certain characteristic and prac- 

 tically invariable symptoms develop; generally within 

 five or ten minutes, sometimes as late as thirty or forty 

 minutes. These symptoms develop in three stages, which 

 are best studied when they do not proceed too rapidly. 

 For this reason the reinjection should be made intra- 

 peritoneally. When given intravenously the symptoms 

 develop so rapidly that a study of the different stages may 

 be difficult or quite impossible. The first stage is that of 

 peripheral irritation. The animal is excited and evidently 

 itches intensely, as is shown by its attempts to scratch 

 every part of its body that it can reach with its feet. The 

 second stage is one of partial paralysis. The animal lies 

 upon its side or belly, with rapid, shallow, and difficult 

 breathing. It is disinclined to move, and when urged to 

 do so shows more or less incoordination of movement, and 

 muscular weakness, with partial paralysis, especially obser- 

 vable in the posterior extremities, which it drags. Rarely 

 the animal dies in this stage. The third, or convulsive 

 stage, begins with throwing the head back at short intervals. 

 The convulsions become general, more frequent and violent, 



