392 INFECTION AND IMMUNITY. 



anaphylatoxins are of similar character but 

 formed through the action of substances which 

 are of specific nature. 

 symptoms of The symptoms of anaphylaxis vary with differ- 

 ^ an j ma | g j^- fa j n ^ e g u i n ea-pig that most 

 constant results are obtained. Symptoms begin 

 at different intervals of time, after the second 

 injection, with different proteins. With animal 

 proteins, they appear in about fifteen minutes 

 after intraperitoneal injection. The symptoms 

 usually appear somewhat later with vegetable pro- 

 teins. The animal becomes restless, there is a 

 tendency to scratch, the hair stands on end, and 

 difficulty in breathing comes on. Paralysis of the 

 hind legs is common with animal proteins but is 

 less common in plant proteins. The respiration 

 becomes spasmodic, the animal is unable to stand, 

 convulsive movements occur, and death follows 

 rapidly when a fatal dose is given. When a non- 

 lethal dose is given symptoms may be delayed for 

 an hour. Death commonly occurs in fatal cases 

 inside of an hour and often in less than half an 

 hour. In intravenous and intracardiac injections, 

 the symptoms follow much more rapidly than in 

 intraperitoneal injections. In subcutaneous injec- 

 tions, the symptoms occur long after injection and 

 are inconstant and much less severe than with 

 other ways of absorption. Fatal results are much 

 more difficult to produce in subcutaneous injec- 

 tions. 



The blood pressure is raised and lowering does 

 not take place until shortly before death. A very 

 important symptom is that described by Pfeiffer, 

 who observed a constant sudden drop in tempera- 



