1 62 PRACTICAL METHODS IN IMMUNITY 



injection of horse serum produced symptoms of respiratory embarrass- 

 ment, convulsions and, at times, death. The primary injection had 

 during the period of incubation sensitized the cells to this particular 

 proteid. 



This phenomenon of sensitization in the case of rabbits bears the 

 name of Arthus, and as applied to guinea-pigs sensitized with diphthe- 

 ria antitoxin sera the name Theobald Smith, and it is stated by Muir 

 and Ritchie that active research as to anaphylaxis may be said to date 

 from the discovery of the phenomenon of Theobald Smith. 



Rosenau and Anderson working with guinea-pigs showed that small 

 doses were efficient for sensitization, that the condition was trans- 

 missible from mother to offspring and that a second animal could be 

 sensitized by being injected with the serum of a sensitized animal. 



This group of symptoms, the so-called anaphylactic shock, which is apt to set 

 in within a few minutes after the second injection, is often preceded by restlessness 

 and great excitement and together with the dyspnoeic manifestations there is cardiac 

 weakness and great fall of blood-pressure. The more serious symptoms and at times 

 death are more apt to appear after intracerebral injections than after intraperitoneal. 

 Subcutaneous injections are least apt to produce anaphylactic symptoms. Our 

 attention to this phenomenon commenced with the study of "serum sickness" or 

 "serum disease." In this an erythematous rash or urticaria associated with more 

 or less oedema comes on after eight to twelve days from the time of the first and only 

 injection of horse serum. It is supposed to be due to the fact that some of the serum 

 originally injected remains unchanged in the tissues so that when the sensitization 

 takes place there is present and at hand the same foreign proteid to bring about 

 anaphylactic symptoms. 



Immunization against anaphylaxis is possible by repeating injection of the sen- 

 sitizing serum or proteid during the period of incubation. 



It is important to note that this hypersusceptibility appears to be 

 very rarely of importance in the matter of the administration of a 

 second injection of diphtheria antitoxin after the period of anaphylactic 

 incubation. 



As a rule the death or untoward effects of the injection of serum are 

 in cases of status lymphaticus. Cases in man do occur, however, but 

 with extreme infrequency, in which within a few minutes after the only 

 injection of serum the patient becomes restless, shows symptoms of 

 cardiac and repiratory embarrassment and may be dead in a very short 

 time. 



According to Rosenau and Anderson individuals who have asthmatic tendencies 

 as well as those who have had serum injections ten to twelve days or longer prior to 



