PROTEIN SENSITIZATION OR ANAPHYLAXIS 321 



be remarked that while the globins do not contain a large 

 amount of the diamino acids, they are rich in the closely 

 related body, histidin, and the relation of this to the highly 

 poisonous |8-i body of Barger and Dale has been mentioned. 

 Certainly there is reason for suspecting that the poisonous 

 group or groups in the protein molecule has some close 

 chemical relationship to the diamino acids. 



Sensitization is Cellular. Dale 1 has shown that the plain 

 muscle of a sensitized guinea-pig contracts when touched 

 with a dilute solution of the homologous protein. This 

 demonstrates that sensitization is cellular. Dale states 

 his conclusions as follows: "(1) Plain muscle from an 

 anaphylactic guinea-pig, freed from all traces of blood and 

 serum, has a very high degree of sensitiveness to the specific 

 sensitizing protein. The plain muscle of the virgin uterus 

 is essentially suited to the demonstration of the condition, 

 and exhibits a definite rise of tonus in response to extreme 

 dilutions of the antigen. (2) The effect is practically imme- 

 diate, i. e., the delay is not obviously more than can be 

 attributed to the method of application of the antigen. 

 (3) The response is not a mere exaggeration of the reaction 

 which normal, plain muscle gives to fresh sera in general. 

 Preparations of purified protein can be obtained (e. g., 

 serum globulin precipitated by Gibson's method, or egg 

 albumen crystallized by Hopkins' method) which have no 

 effect on the normal plain muscle, but are as toxic for the 

 anaphylactic plain muscle as the native proteins. (4) 

 One dose of the specific antigen, in sufficient concentration 

 to produce "maximal" response of the anaphylactic plain 

 muscle, completely desensitizes the latter to further doses 

 of any dimensions, provided that the experiment is not 

 complicated by the use of an antigen preparation of normal 

 toxicity. Either normal or anaphylactic plain muscle gives 

 repeated responses to successive large doses of a normally 

 toxic serum or other native protein, but this phenomenon 

 is not anaphylactic response. (5) When sensitizing doses 



1 Jour, of Pharm., 1913, iv, 167. 

 21 



