DEMONSTRATION OF SPECIES DIFFERENTIALS 505 



tive (Lance field). Also, specific nucleo-proteins isolated from streptococci 

 could readily serve as sensitizers and likewise induce shock. 



In general, it seems then that the specificity of the anaphylactic reactions 

 is of about the same order as that of the ordinary precipitin and complement 

 fixation tests. There is no indication that by means of the anaphylactic 

 reaction it may be possible to differentiate between individuality differentials, 

 although this reaction may very well serve for the demonstration of species 

 differentials and of chemical substance-specificity. 



Wells and Osborne were able to find in every case in which two sub- 

 stances were specific, as far as the anaphylactic test indicated such specificity, 

 a definite chemical, in contrast to a mere stereoisomeric constitutional differ- 

 ence between these two substances ; and this was true not only of the alcohol 

 soluble plant proteins, but also of five substances derived from ovomucoid. 

 From former data it might have been expected that also stereoisomeric dif- 

 ferences between substances might give rise to specific serological reactions, 

 and, as we shall see later, Landsteiner subsequently succeeded in demonstrat- 

 ing effective stereoisomeric differences in haptens by means of the precipitin 

 reaction. 



There still remains one point to be discussed. We have noticed that in the 

 experiments of Wells and Osborne, and in those of Lewis and Wells, the 

 specificity of the reactions was either absolute, one substance sensitizing 

 exclusively against the substance used for the production of anaphylactic 

 shock, or the reaction did not make possible the distinction between analogous 

 substances from related plants. The quantitative gradations in the reactions 

 corresponding to the gradations in phylogenetic relationship seemed to be 

 lacking entirely in the earlier experiments, although there was an indication of 

 such gradations observed in the later work. Wells, Osborne and Lewis used 

 in their experiments purified substances rather than mixtures of substances 

 as they occur in ordinary extracts from blood or organs. Their findings might 

 suggest that the gradations which are so commonly observed in the case of im- 

 mune reactions, result from the use of mixtures of antigens as they are present 

 in the tissues and bodyfluids of organisms ; from this point of view the graded 

 relationships of different species would depend upon differently constituted, 

 quantitatively graded mixtures of various substances which are characteristic 

 of these species, and not on gradations in the structure of a complex protein 

 or on a combination of a specific hapten of a non-protein nature, which 

 differs in a graded way in different species, with the same or a similar protein 

 serving as carrier. However, this conclusion would not be in agreement with 

 some other well established facts. Thus we may recall the immunological 

 differences between the whites of chicken and duck eggs, as shown in the 

 anaphylaxis experiments of Dakin and Dale. Such differences are graded, 

 although these investigators used crystalline substances in their experiments ; 

 in this case, therefore, the gradation in the reactions must have depended 

 in all probability on graded differences in the chemical structure of single 

 substances. 



We have seen that by means of immunization it is possible to demonstrate 



