1058 ABDERHALDEN'S REACTION AND "PROTECTIVE" FERMENTS 



etc.), the blood may contain a considerable quantity of such substances.' On the other hand, 

 the concentration of dialyzable protein constituents of the blood is physiologically increased 

 during, and for some time after, the active digestion of food. To avoid this the blood should 

 be collected as long as possible after the last meal. In pathological conditions in which 

 the amount of dialyzable protein constituents is high and cannot be regulated at will, it is 

 necessary to free the serum of such substances by means of a preliminary dialysis.^ Only 

 after the serum has been thus prepared can the Abderhalden test be performed. 



Substratum. — The ideal substratum would consist of a pure specific substance. In prac- 

 tice, however, this is possible only in exceptional cases, and mainly in experimental work.'' 

 In diagnostic work the substrata are usually represented by tissues, and it is evident that to 

 approach the highest standard the tissues would have to be freed as much as possible of 

 blood, connective tissue, and of non-specific elements in general.'' Material thus obtained 

 must be ground to a pulp, quickly coagulated, and extracted repeatedly with boiling water 

 to remove all soluble substances reacting with ninhydrin. 



When this has been accomplished, it remains to titrate the substratum, i.e., to ascertain 

 what quantity of substratum is to be used in the test. If the bulk of the tissue representing 

 substratum is composed of specific elements, a much smaller amount is needed for the reac- 

 tion than is the case when an appreciable portion of the substratum consists of non-specific 

 tissue constituents. An excess of substratum often reacts with normal as well as with specific 

 serum, whereas an insufficient amount may fail to react at all. It is evident that each sub- 

 stratum must be standardized before it can be used in the test. The stock of standardized 

 substratum must be sterilized by boiling and preserved aseptically under a layer of toluol, at 

 low temperature. 



Selection of dialyzing thimbles. — Equally important is the selection of suitable dialyzing 

 thimbles.5 It is evident that the selective permeability of the thimbles can be relied upon 

 only on the condition that the dialyzing membrane is intact through all the surface of its 

 contact with the solution. If, for instance, there should be even the slightest puncture in a 

 membrane, the unaltered protein will go through and render the reaction valueless. On the 

 other hand, experience has shown that among the membranes used in dialysis there exist 

 wide individual variations in permeability to dialyzable substances.* Thus, for instance, of 

 two apparently identical membranes, one may let through peptones with great ease, whereas 

 the other may let them through very slightly, or sometimes not at all. As the whole outcome 

 of the Abderhalden test depends on the uniform permeability of thimbles, as well as on freedom 



' Abderhalden, E.: Milnchen. med. Wchnschr., 61, 401. 1914; Abwehrfermente (4tli ed.), p. 257. 

 Berlin, 1914; Lange, C: Berl. klin. Wchnschr., 51, 785. 1914. 



2 Schlimpert, H., and Issel, E.: Munchen. med. Wchnschr., 60, 1758. 1913. 



3 Wells, H. G.: Chemical Aspects of Immunity. American Chemical Society, 1925; Elsesser, O.: 

 /. Infect. Dls., 19, 655. 1916; Smith, G. H., and Cook, M. W.: ihid., 18, 14. 1916; Smith, G. H.: 

 ibid., 16, 313 and 319. 1915. According to Wells {op. cit.), "There undoubtedly does commonly occur 

 a greater proteolysis with specific antigen than if some other protein is present" (p. 210). However, 

 according to this author, even with a specific antigen the reaction is less sensitive than is the ana- 

 phylactic reaction, for instance (p. 176). 



4 Lange, C, Biochem. Ztschr., 61, 193. 1914; Frank, Rosenthal, and Biberstein: cited from 

 Domarus, A., and Barsieck, W.: Miinchen. med. Wchnschr., 61, 1553. 1914. 



s The dialyzing thimbles used in performing the Abderhalden reaction are especially made for 

 this purpose by Schleicher and Schiill. 



^Werner, P., and Winiwater, A.: Wien. klin. Wchnschr., 26, 1841. 1913; Mosbacher, E., and 

 Port, F.: Deutsche med. Wchnschr., 40, 1410. 1914; Abderhalden, E.: Abicehrfermenle (4th ed.), pp. 

 208, 278. Berlin, 1914. 



