ANAPHYLACTTC SHOCK 169 



if large amounts of the serum be given extending over days 

 or even weeks, but a second injection of serum given after 

 a first injection with an interval of twelve days or more 

 between the two injections is liable to be followed by 

 effects which may be more or less serious, constituting 

 the so-called " anaphy lactic shock " or " serum disease," 

 or immediate or accelerated reactions, " supersensitisation," 

 may ensue (see p. 161). 



In anaphy lactic shock, plain muscle contracts and Dale 1 

 has used the excised uterus of sensitised guinea-pigs to 

 give a graphic record of the action of the reacting dose. 

 Specificity is shown by the fact that the uterus of a guinea- 

 pig sensitised with sheep-serum contracts only when flooded 

 with a reacting dose of sheep-serum and not with any 

 other serum. The animal may be sensitised with two or 

 three different proteins and then the uterus contracts in 

 turn to each reacting dose of the different proteins. Once 

 the reacting dose has been given and the uterus has con- 

 tracted, the muscle is no longer sensitive to the protein. 



The symptoms of anaphylactic shock are nausea and 

 vomiting, small and rapid pulse, faintness or more serious 

 heart failure, dyspnoea with rapid and shallow respiration 

 and feeling of suffocation, collapse, rigors, convulsions, 

 and even coma. The severity of the symptoms varies in 

 different cases, and the symptoms usually pass off in the 

 course of an hour or two ; but a few fatal cases have been 

 recorded. Death is easily produced experimentally, and, 

 post-mortem, scattered ecchymoses are found and a dis- 

 tended condition of the lungs due to spasm and contraction 

 of the bronchioles, to which the fatal event is due. 



In the immediate reaction, rash, pyrexia, joint pains, 

 vomiting, rigors, and occasionally convulsions and collapse 

 occur, generally within six hours after the second injection 

 of serum. In the accelerated reaction, these phenomena 



1 Jmirn. Pharmacd. and Exp*r. Therapeutics, IV, 1913-14, p. 167. 



