PROTEIN SENSITIZATION OR ANAPHYLAXIS 333 



have been ascertained in regard to this matter indicate that 

 sensitization is secured only by alteration in the cell and that 

 in some cells the newly developed function is more persistent 

 than in others. 



The facts of cross-sensitization seem in harmony with our 

 view that the protein molecule contains one or more special 

 sensitizing groups. The white of hen's eggs sensitizes to itself, 

 less perfectly to the white of duck's eggs, and very imper- 

 fectly or not at all to the white of robin's eggs. The serum 

 of man's blood sensitizes to itself and less fully to that from 

 the ape. Horse serum sensitizes to itself, and less fully 

 to that of the donkey. Certain non-pathogenic acid-fast 

 bacteria sensitize in some degree to the tubercle bacillus. 

 In short, the phenomenon of sensitization, like that of pre- 

 cipitation, may be employed to show biological relationship. 

 All this seems in harmony with the view that the specificity of 

 sensitization depends upon the similarity or dissimilarity in the 

 chemical structure of protein molecules from different sources. 



Doerr 1 makes the following statement concerning Fried- 

 berger's anaphylatoxin: So far as the matrix of the poison 

 is concerned it is highly improbable that it comes from the 

 bacteria or other antigens. That the most diverse proteins 

 should yield the same poison seems improbable. The theory 

 that the poison comes from the amboceptor, as held by 

 Wassermann and Keysser, is still less probable. That the 

 anaphylatoxin comes from the blood-serum, the one constant 

 factor in all the experiments in its production, is most prob- 

 able. During its formation or in the process of blood coagu- 

 lation, a poison is formed, but the serum obtained, after 

 coagulation is complete, is not poisonous on account of the 

 presence of antibodies. When the serum is digested with 

 bacteria, precipitates, etc., the latter absorb the antibodies 

 and thus the serum again becomes poisonous. That ana- 

 phylatoxin can be obtained when there are no formed elements 

 present, as for instance when inactivated horse serum is 



1 Handbuch d. path. Mikroorganismen by Kolle and Wassermann, second 

 edition, ii, 947. 



