IDIOSYNCRASY AND ANAPHYLAXIS 557 



differences may perhaps exist between them. Thus, while the typical immune 

 bodies are supposed to be serum globulins and are therefore not diffusible 

 through collodion membranes, it has been maintained that the antibodies, 

 which make possible the Prausnitz-Kiistner reaction in serum disease and 

 other kinds of idiosyncrasy, are dialysable. 



As to the relationship between anaphylaxis, immunization and organismal 

 differentials, states of immunization as well as of anaphylaxis may be elicited 

 by substances carrying organismal differentials, organ differentials, and, 

 besides, by substances which have no relation to either. These various sub- 

 stances may also induce a reaction in the sensitized animal. Phenomena of 

 immunity can, moreover, be elicited against individuality differentials, but it 

 is not yet certain that anaphylaxis to organismal differentials, which are so 

 nearly related to those of the host, has been observed. 



As far as idiosyncrasy or so-called allergy is concerned, in many instances 

 this condition seems to be directed against a species differential. Thus, in 

 idiosyncrasy against hair of a foreign species the state of hypersensitiveness 

 is a specific one, affecting the hair of a certain species, although overlapping 

 reactions do occur (W. Storm van Leeuwen). The experiments of Longcope, 

 O'Brien and Perlzweig, and those of Forster, make it probable that, on the 

 whole, the reactions against horse dander are specific and distinct from those 

 against horse serum, although according to Forster cross-reactions take 

 place to a limited extent. There may, therefore, be a common species differ- 

 ential involved also in these reactions. We have already referred to the observa- 

 tions of Duke, in which hypersensitiveness to human milk was not associated 

 with hypersensitiveness to cow's milk. In a case of experimentally produced 

 hypersensitiveness of human skin to various kinds of serum by means of 

 intracutaneous injection, Frei, Biberstein and Frohlich found a similar over- 

 lapping of the reactions to that observed in the precipitin reactions. The 

 relationship of the species used determined the specificity or lack of specificity 

 of the reactions. However, here we have to deal with anaphylaxis rather than 

 with idiosyncrasy in the strict meaning of this term. In anaphylaxis, precipitins 

 may be the antibodies involved, according to Opie. 



While, therefore, organismal differentials may be concerned in idiosyncrasy 

 as the exciting agents, they do not, on the whole, play a very prominent part ; 

 on the contrary, it seems to be characteristic of idiosyncrasy that relatively 

 simple substances, quite distinct from the complex substances possessing 

 organismal differentials, are the principal agents ; it is assumed especially in 

 the case of drug idiosyncrasies that the person's own serum plays the role of 

 a carrier, to which the hapten attaches itself. But this is by no means certain ; 

 it is possible that these substances may act directly on the cell protoplasm of 

 the sensitive tissues and here call forth specific reactions. 



Also, other investigations indicate the relative independence of conditions 

 of hypersensitiveness from strange organismal differentials. Thus while in 

 general, in immunization against organ differentials it was advisable to 

 select as antigens sera of a heterogenous nature, which acted as carriers for 

 the specific organ-specific haptens, in order to produce skin hypersensitiveness 



