680 EXPERIMENT STATION RECORD. 



Pneumonia in a* Camel's Lung (pp. 353, 354) are considered by R. G. Archi- 

 bald; and Coccidiosis of the Intestine in the Goat (pp. 355-359) and A Few 

 Notes on the Protozoa Parasitic in Bufo regularis in Khartum (pp. 359-361) 

 are presented by A. C. Stevenson. 



Is the specificity of the anaphylaxis reaction dependent on the chemical 

 constitution of the proteins or on their biolog-ical relations? — II, The bio- 

 logical reactions of the vegetable proteins, H. G. Wells and T. B. Osborne 

 {Jour. Infect. Diseases, 12 (1913), No. 3, pp. 3Jfl-35S).— In previous work (E. 

 S. R., 25, p. 9) it was shown that zein, the alcoholic-soluble protein of corn, 

 did not produce an anaphylaxis reaction in animals sensitized with gliadin or 

 hordein. It was, however, found that gliadin from either wheat or rye inter- 

 acted as if they were one and the same protein. 



" Guinea pigs, sensitized with gliadin from wheat or i*ye, give strong ana- 

 phylactic reactions with hordein from barley, but these are not as strong as 

 the reactions obtained with the homologous protein. Similar results are 

 obtained if the sensitizing protein is hordein and the second injection is gliadin. 

 We have here a common anaphylaxis reaction developed by two chemically dis- 

 tinct, but similar, proteins of different biological origin, thus indicating that 

 the specificity of this reaction is determined by the chemical constitution of 

 the protein rather than by its biological origin. This is in harmony with the 

 fact that chemically closely related proteins have, as yet, been found only in 

 tissues that are biologically nearly related. 



" Complete protection to subsequent injection of the homologous protein was 

 not afforded by a reaction to the heterologous protein, thus indicating the 

 presence of two or more individual proteins in the preparations of gliadin 

 and hordein, one of which is common to both, or else the presence in gliadin 

 and hordein of both common and specific reactive groups. The chemical evi- 

 dence is in favor of the latter conclusion. The foregoing indications are sup- 

 ported by saturation experiments, which show that when guinea pigs are sen- 

 sitized with either gliadin or hordein, and then saturated with the heterologous 

 protein, they still react strongly when injected with the homologous protein. 



" Gliadin and glutenin react anaphylactically with one another, although 

 chemical comparisons have shown them to be proteins of distinctly different 

 types. Evidence was obtained that the reactions between these proteins should 

 not be ascribed to contamination of the preparations with one another, i. e., to 

 an incomplete separation of the two. The conclusion appears justified that 

 these chemically distinct proteins contain common reactive groups. Guinea 

 pigs sensitized with glutenin do not react anaphylactically with hordein, thus 

 showing that the reaction between gliadin and glutenin is not caused by an in- 

 complete separation of these latter proteins, but by reactive groups common to 

 gliadin and glutenin, but absent from hordein. 



" From the results of these experiments it seems probable that the entire 

 protein molecule is not involved in the specific character of the anaphylaxis 

 reaction, but this is developed by certain groups contained therein, and that 

 one and the same protein molecule may contain two or more such groups. It 

 may well be that the intact protein molecule is involved in the reaction (for 

 there is but little evidence that anything less than an intact protein molecule 

 is capable of producing the typical reaction), but that certain groups determine 

 the specificity. Such a conclusion can not be accepted as final until we have 

 some means whereby the chemical individualitj'- of a protein can be estab- 

 lished. Until then the possibility will remain that our so-called pure prepara- 

 tions of protein consist of mixtures, or combinations, of proteins which have 

 thus far resisted £fll efforts to separate them. In this latter case the reactions 



