CHAPTER XXIII. 



ANAPHYLAXIS. 



Attention has already been called to the fact 

 that an individual may be more susceptible to 

 infections at one time than at another through 

 various accidental conditions, as exposure and 

 exhaustion. This, however, is not a specific hyper- 

 susceptibility and is usually more or less transient. 



In contrast to this accidental condition, stands 

 a specific susceptibility which is now commonly 

 known as anaphylaxis. The condition of the in- 

 dividual or animal is spoken of by Y. Pirquet as 

 allergy (AUergie), a word which conveys the idea 

 of an altered power of reaction on the part of the 

 animal body. 



V. Pirquet's conception of allergy is best de- 

 scribed in his own words, in which he uses vac- 

 cination and revaccination as an illustration. 

 "Vaccinia, with which we can at any time institute 

 an infection, is just as much an infectious disease 

 as is variola, of which it represents an attenuated 

 form. Let us inoculate one person who was 

 vaccinated two years previously and who, accord- 

 ing to the customary view, is immune, with a 

 drop of lymph. Then inoculate another who has 

 not gone through this process and attend it 

 closely. Now will the immune person show ab- 

 solutely nothing? On the contrary, when we re- 

 turn after 24 hours, we find in the one who 

 received his first inoculation (the normal person), 

 a small crust showing no reaction, while in the 



