PHENOMENA OF ANAPHYLAXIS 537 



Man. When it is remembered that anaphylaxis and immunity are 

 closely interwoven, and that anaphylaxis may be but a step toward 

 securing prophylaxis and immunity, it will readily be understood that 

 under the varying conditions of different injections the phenomena may 

 be quite dissimilar. One of the best known examples of a general 

 anaphylactic phenomenon in man is that following the injection of a 

 foreign serum, as, e. g., horse serum (diphtheria antitoxin), which is 

 characterized by an itching urticarial eruption, fever, and joint pains, 

 and which is commonly known as " serum sickness." Fortunately, the 

 severer and fatal forms of anaphylaxis in man are extremely rare, most 

 cases having occurred in persons known to be hypersensitive to horse 

 protein or in those suffering from the condition known as status lym- 

 phaticus. Familiar local anaphylactic reactions are the tuberculin, 

 mallein, and luetin reactions. With this brief statement we shall pass 

 to a consideration of anaphylaxis in the lower animals, experimentation 

 having given us some insight into the mechanism of the process. Ana- 

 phylaxis in man and the relation it bears to immunity and disease, will 

 be discussed again in Chapter XXVIII. 



Guinea-pig. This animal gives the most constant and the most 

 intense symptoms. According to Doerrr, guinea-pigs are four hundred 

 times as sensitive an anaphylactic reagent as the rabbit. 



Horse serum, when injected into normal guinea-pigs, gives rise to 

 no symptoms. As much as 20 c.c. may be injected into the peritoneal 

 cavity, and small amounts may even be injected into the brain without 

 causing any untoward symptoms. 



When a small dose of serum is injected intravenously, intraperito- 

 neally, or subcutaneously, and ten days later a second injection is made, 

 the animal develops symptoms of acute anaphylactic asphyxia, which, 

 in the majority of instances, terminates fatally. " In five or ten minutes 

 after injection the pig becomes restless and then manifests indications 

 of respiratory embarrassment by scratching at the mouth, coughing, 

 and sometimes of spasmodic, rapid, or irregular breathing; the pig 

 becomes agitated, and there is a discharge of urine and feces. This 

 stage of exhilaration is soon followed by one of paresis or complete 

 paralysis, with arrest of breathing. The pig is unable to stand, or if it 

 attempts to move, falls upon its side; when taken up it is limp; spas- 

 modic, jerky and convulsive movements now supervene. This chain of 

 symptoms is very characteristic, although they do not always follow in 

 the order given. Pigs in the state of complete paralysis may fully 

 recover, but usually convulsions appear, and are almost invariably a 



