536 ANAPHYLAXIS 



after a time a specific hypersensitiveness of the animal for this pro- 

 tein will appear. After a definite interval, a second injection of the 

 same substance, harmless in itself, may produce an itching rash and 

 fever or violent symptoms of illness, and rapid death may even occur 

 in an animal so inoculated. In other words, the first injection of the 

 protein (serum, milk, egg-albumen, etc.) produces no symptoms, but 

 serves to alter the power of reaction on the part of the body cells by rendering 

 them unusually sensitive or susceptible to the same or to closely related 

 foreign protein. Therefore, as defined by Rosenau, anaphylaxis may be 

 considered as "a condition of unusual or exaggerated susceptibility of the 

 organism to foreign proteins." 



Terminology. 1 As previously stated, the word " anaphylaxis "(ana, 

 against, and phylax, guard, or phylaxis, protection) was given to the 

 condition by Richet, because he considered it one "without protection," 

 or a state just the opposite to immunity, or prophylaxis. In the sense 

 in which the phenomenon is now regarded the word is a misnomer, for 

 we look upon the condition of hypersusceptibility as a step toward the 

 attainment of a state of immunity, and as a distinct benefit and ad- 

 vantage to the organism. The term " allergy," introduced by von 

 Pirquet, is more appropriate, as it expresses the condition of the body- 

 cells, i. e. } their hypersensitiveness or altered reactivity, regardless of 

 any theories we may entertain as to the manner in which this change is 

 brought about or manifested. ' The word anaphylaxis has, however, come 

 into general use, and with this explanation, we may continue to so use it. 



The term anaphylactogen is applied to the protein, as serum, milk, 

 egg-albumen, etc., which sensitizes the body-cells; sentizer is also a good 

 word, and the process of rendering body-cells hypersensitive by ad- 

 ministering a foreign protein has been called sensitization. In von 

 Pirquet's nomenclature the protein would be called an allergen. 



The term anaphylatoxin is applied to the toxic substance believed to 

 be formed at the time of reinjection of the protein, and is regarded as 

 responsible for the lesions and symptoms of anaphylaxis. In the belief 

 that anaphylaxis resembles an intoxication, the second inoculation of 

 protein is frequently spoken of as the intoxicating dose. 



PHENOMENA OF ANAPHYLAXIS 



The essential symptoms and lesions of anaphylaxis vary in the dif- 

 ferent animals, and, indeed, they have been found to vary among animals 

 of the same species under different experimental conditions. 



