556 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



proteins, may serve as antigens and call forth anaphylactic states. Landsteiner 

 employed for this purpose heterogenous serum and observed that the same 

 hapten in combination with a heterogenous serum, different from that which 

 was used for sensitization, may react with the antibody ; under certain condi- 

 tions even the hapten, as such, may be able to give rise to this reaction. Accord- 

 ing to Klopstock and Selters, it is possible to sensitize guinea pigs against 

 diazotized atoxyl by intravenous injection of a combination of this atoxyl 

 preparation and guinea pig serum. However, in order to accomplish a sensitiza- 

 tion by means of subcutaneous application of the antigen it is sufficient to 

 inject diazotized atoxyl alone, without the combination with guinea pig serum. 

 A reaction indicating hypersensitiveness is elicited in the sensitized guinea 

 pig by the intravenous injection of diazotized atoxyl and guinea pig serum; 

 but again, a reaction can also be obtained by subcutaneous injection of the 

 atoxyl preparation alone, without the combination with guinea pig serum. In 

 the latter case the reaction consists in a localized necrosis, a condition closely 

 resembling the Arthus phenomenon. The authors assume that after sub- 

 cutaneous injection of the atoxyl preparation, the sensitized animal's own 

 serum combines with the atoxyl and acts as carrier. In the case of sensitiza- 

 tion with simple chemical substances, such as certain drugs and the extract 

 of primula, it is likewise possible that a combination of the hapten with autog- 

 enous serum takes place during the process of sensitization, and also pre- 

 ceding the idiosyncratic reaction. But as far as we are aware, a direct proof 

 that autogenous serum may serve as carrier in the process of sensitization to 

 such antigens has not yet been given. 



Experiments of Landsteiner and Chase showed especially clearly the es- 

 sential similarity between the conditions of hypersensitivity and anaphylaxis ; 

 these conditions differ in regard to the site of the body which reacts in these 

 states and in the greater difficulty with which the reactions of idiosyncrasy 

 become manifest. Both are antibody reactions. Thus, intraperitoneal injections 

 of stromata of guinea pig erythrocytes, conjugated with picric acrid or with 

 dinitrofluorobenzene preceded by injections of dead tubercle bacilli called forth 

 both states. Subsequent applications of picric acid and blood serum mixtures 

 induced general anaphylactic reactions, as well as local skin responses. Instead 

 of sensitizing with picric acid-erythrocyte stromata it was possible also to 

 cause sensitization by injections of picric acid-guinea pig serum; however, 

 picric acid and horse serum combinations produced only a state of anaphylactic 

 sensitization but not one of skin hypersensitivity ; to produce the latter, it was 

 necessary to use homoiogenous serum. These experiments make it very 

 probable that antibodies are involved in both anaphylaxis and skin hypersensi- 

 tiveness. In such processes of sensitization, hereditary factors determining 

 degrees of response of the individuals may enter (Chase) ; this would be in 

 accordance with the findings of Lewis, Lurie and Webster, which have estab- 

 lished hereditary differences between the susceptibility to various bacterial 

 and virus infections of different strains of animals within the same species. 



Though all the facts known so far point to the conclusion that idiosyncrasy 

 and anaphylaxis are closely related or identical phenomena, certain minor 



