TOXIN AND ANTITOXIN 133 



steiner and v. Eisler 42 has brought out the fact that extraction of 

 brain tissue with ether materially reduces its toxin-binding powers 

 by removing fatty or lipoidal substances, such as cholesterin and 

 lecithin. And it has indeed been confirmed that lipoids can possess, 

 in many instances, binding properties not only for toxins but for 

 other forms of antibodies. On the basis that at least a part of the 

 toxin absorption by brain emulsions depends upon such lipoidal fixa- 

 tion, the results of Besredka are readily explained, but were this the 

 sole cause of toxin fixation by these tissues it would indeed be diffi- 

 cult to interpret the phenomenon, with Wassermann and Takaki, in 

 support of Ehrlich's theory. For, without going into further refine- 

 ments, the fact of the probable proteid, certainly not lipoidal, nature 

 of the antitoxins, discussed in a previous section, would alone serve 

 to distinguish the two modes of toxin fixation. 



However, a number of facts have been ascertained which show 

 that, although the lipoids play some part in the antitoxic action of 

 brain cells, they do not by any means account for the entire process. 

 In the first place it is found that the heating of brain emulsions al- 

 most completely removes their power to bind the toxin, while no 

 such reduction of the fixative property follows the heating of lipoids 

 like cholesterin or lecithin. The experiments of Marie and Tif- 

 feneau 43 have done much to clear up the confusion regarding this 

 point. They determined that the "lipoidal binding" constituted only 

 about one-tenth of the total binding power of the brain emulsions, 

 by showing in the first place that only one-tenth of the total was left 

 after heating, and that all but one-tenth could be destroyed by sub- 

 jecting the tissue to the action of proteolytic enzymes. It appears 

 from this that a large part, at any rate, of the toxin fixation of the 

 brain tissues is dependent upon substances of an albuminous nature, 

 a smaller but definite part being dependent upon fixation by lipoids, 

 a phenomenon entirely apart from the former in underlying princi- 

 ples. This would, it seems, both justify the original interpretation 

 of Wassermann and still explain the apparently contradictory results 

 of Besredka and others. 



42 Landsteiner and v. Eisler. Centralbl. f. Bakt., Vol. 39, 1905. 



43 Marie and Tiffeneau. Ann. de I'Inst. Past., Vol. 22, pp. 289 and 644, 

 1908. 



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