504 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



in the various species of the wheat group and their differences from those 

 belonging to the corn group. However, Gortner also refers to differences in 

 the number of chromosome sets which exist between different members of the 

 wheat group and to corresponding differences in hybridizability between these 

 species. It seems, then, that here cytological differentiations and the mode of 

 interaction of spermatozoa and ova of various species during fertilization are 

 much finer tests for the constitution of organismal differentials than the 

 chemical analysis of the alcohol soluble proteins, or the serological methods, 

 such as anaphylaxis or complement fixation. 



In the case of some animal substances, Dakin and Dale, using the uterus 

 strip method for the diagnosis of an anaphylactic state, were able to differen- 

 tiate between the crystalline egg albumens of hen and duck. The specificity of 

 this reaction could also be shown by means of specific desensitization. In more 

 recent years, Landsteiner's demonstration that certain antigens are complex 

 and consist of a combination of non-protein hapten and a foreign protein 

 which acts as a carrier, was followed by attempted immunization against these 

 complex antigens, and in this connection use was made also of anaphylaxis 

 as a test for the specificity of various antigens and of the relative significance 

 of these two component parts of the antigen. 



In such experiments, in order to sensitize a guinea pig against a hapten, it 

 was necessary to inject the latter in association with a foreign protein, the 

 hapten alone not being able to cause sensitization. As to the means of produc- 

 ing shock in actively or passively sensitized guinea pigs through a second 

 injection of the antigen, somewhat divergent results were obtained. Land- 

 steiner could, in some cases, but not in all, produce anaphylactic shock in 

 guinea pigs sensitized with an azodye-protein combination by injecting the 

 azodye alone. It has even been maintained that it is possible to sensitize 

 guinea pigs by injection of diazotized atoxyl alone and, moreover, to cause 

 shock in animals thus sensitized by injection of the same substance; it was 

 further assumed that under these conditions the injected animal's own serum 

 may act as carrier. In guinea pigs sensitized against the polysaccharides, 

 which are responsible for the type-specificity of pneumococci, it was necessary 

 to inject the animal with the same kind of polysaccharide, in combination with 

 a protein, for the production of shock. On the other hand, intradermal injec- 

 tion of the type-specific pneumococcus polysaccharide alone could bring about 

 a specific inflammatory skin reaction. 



However, a specific glucoside, which itself was not able to produce shock 

 nor, correspondingly, to cause precipitation with antisera, inhibited in a specific 

 manner the condition of shock, which otherwise would have resulted in 

 sensitized guinea pigs, by the injection of the glucoside in association with a 

 protein (Tillet, Avery and Goebel). Similarly, the hapten inhibited precipita- 

 tion, which would ordinarily have resulted from the precipitin-antigen com- 

 bination. 



In the case of streptococci the specific carbohydrate, without the addition of 

 foreign protein, could induce shock in passively sensitized guinea pigs, pro- 

 vided the immune serum used for passive immunization had been very effec- 



