372 INFECTION AND RESISTANCE 



the brief summary we have given of Rosenau and Anderson's work. 

 These authors use the adjective "quantitative," by which they simply 

 mean to convey that the specificity here is not absolute, any more than 

 it is absolute in the case of any of the known serum reactions. An 

 animal sensitized with a certain variety of protein, animal serum, etc., 

 reacts with disproportionately greater delicacy to a second injection 

 of the same variety than of any other substance. In fact, apiart from 

 a few cases mentioned by Gay and Southard, there are not many in- 

 stances of marked non-specific anaphylactic reactions. Still we would 

 expect here, as in other serum reactions, a certain limitation in the 

 degree of specificity, and Otto recommends the less delicate subcu- 

 taneous method of testing for all experiments in which questions of 

 specificity are involved. This point we will touch upon a little later. 



An interesting addition to our knowledge of such specificity was 

 made by experiments of Rosenau and Anderson, 38 which showed that 

 a guinea pig could be rendered separately sensitive at one and the 

 same time to blood serum, eggwhite, and milk, reacting specifically 

 to each on second injection. 



In anaphylaxis, again analogous to antibody reactions in general, 

 the specificity, as a rule, is one of species. In other words, the pro- 

 tein of any animal is specific for the proteins of its particular spe- 

 cies generally, there being definitely similar characteristics in the 

 body proteins of animals of like species which, though chemically 

 indefinable, are nevertheless delicately determinable by biologic reac- 

 tions. In considering specificity of precipitins, however, we have 

 seen that there are exceptions to the specificity of species expressed 

 in the phenomenon of so-called organ specificity. The same thing- 

 has been shown for anaphylaxis. Kraus, Doerr, and Sohma 39 were 

 able to show that animals sensitized with protein from the crystalline 

 lens were hypersusceptible to lens protein generally, whether this 

 came from the species from which the original lens was taken, or 

 whether some other variety of animal had furnished it. On the other 

 hand, animals so sensitized, while hypersusceptible to lens protein 

 generally, did not react to injections of homologous blood. 40 In 

 other words, this organ contains a characteristic variety of antigen 

 (protein) peculiar to this kind of organ throughout the different 

 animal species, but not common to other tissues and organs of the 

 same animal. Results similar to these were obtained by von Dun- 

 gern and Hirschfeld 41 in the case of testicular protein, although 

 here the phenomenon seemed to be less rigidly organ-specific than 

 in the preceding case. These writers worked not with the systemic 



38 Rosenau and Anderson. Jour. Inf. Dis., Vol. 4, 1907. 



39 Kraus, Doerr, and Sohma. Wien. klin. Wocli., No. 30, 1908. 

 40 Andrejew. Arb. a. d, kais. Gesundh. Ami., Vol. 30,. 1909. 



41 von Dungern and Hirschfeld. Zcitschr. f. Immunitatsforschung, 4, 

 1910. 



