130 CONTEMPORARY SCIENCE 



istence of such a class, and to inquire how far certain 

 individual diseases may be considered as belonging 

 to it. 



ANAPHYLAXIS 



Allusion has several times been made to the hyper- 

 sensitive state which is often regarded as the opposite of 

 the immune condition. Because the latter is conceived as 

 protective and hence is spoken of as being prophylactic, 

 the former in turn has been named anaphylactic. The 

 obvious distinction between the two conditions is simply 

 defined by the statement that while the immunized animal 

 shows a greater degree of resistance to a second inocula- 

 tion of the materials used for immunization, the anaphy- 

 lactized animal on the contrary shows a heightened sus- 

 ceptibility. 



The history of anaphylaxis illustrates the manner in 

 which the rapidly growing knowledge of immunity reacted 

 on the appreciation of this condition. It now appears 

 that the physiologist Magendi, who flourished in the first 

 quarter of the nineteenth century, first noted that an 

 animal which had borne without apparent effect one in- 

 jection of a quite harmless protein such as egg white, 

 reacted severely to a second injection of the same kind of 

 material given after an interval of days. No further con- 

 temporary attention seems to have been given to this iso- 

 lated incident, and it was not until 1894 that the speaker 

 chanced again upon the phenomenon. He was engaged 

 upon a study of the pathologic action of the toxalbumins, 

 and his attention was attracted by recent experiments on 

 the similar globulicidal (or red blood corpuscle destruc- 

 tive) action of certain alien blood serums, such for ex- 

 ample as the serum of the dog for the red globules of the 

 rabbit. Since animals could be rendered immune to the 

 toxalbumins, the attempt was made to make rabbits im- 

 mune to dog's serum, but without success. On the con- 

 trary, it was found that animals which had withstood one 



