820 STUDIES IX IMMUNITY. 



this fluid can <uilv have a flocculating action they arc evidently 

 not responsible for producing this suspension.* 



We believe (although our opinion is based on no irrefutable 

 experimental proof) that if ferric hydrate and CaFl 2 fail to be pre- 

 cipitated by the electrolytes of fluid L, and if barium sulphate 

 remains in a state of fine suspension in this fluid, it is due to the 

 fact that they are held in suspension by the colloidal substances of 

 an albuminous nature that have come from the corpuscles through 

 Laking. The phenomenon, indeed, is identical with the dissociat- 

 ing effect of serum on barium sulphate, to which we have already 

 referred and which we shall presently again consider. This dis- 

 sociating power in the laked fluid can be exhausted, as can the 

 same power in serum, and if we presume that the precipitate is due 

 to some substance we may suppose that this substance can be 

 removed from the laking fluid. As a proof let us add a rather large 

 amount of CaFl, to fluid L containing no stromata; after 15 minutes' 

 contact we will remove the CaFl 2 by centrifugalization and obtain, 

 on decanting, a fluid A which differs from fluid L only in having 

 been subjected to a large amount of fluoride. We find that the 

 sedimentation and flocculation of the various substances to which 

 we have referred, although prevented by fluid L, occur very readily 

 in fluid A. And, what is more, an agglutination of red blood cells 

 by suspensions and by ferric hydrate takes place perfectly in A, 

 although it does not occur in L. 



The large amount of CaFl 2 , then, has removed something from 

 fluid L that prevents the flocculation of CaFl 2 and of ferric hydrate 

 by electrolytes as well as the sedimentation of barium sulphate. 

 The property of preventing the agglutinating of corpuscles by 

 means of these three substances has also been removed from fluid L 

 bv this treatment. We believe that this substance or substances 

 are albuminous colloids that come from the corpuscles as a result 

 of the laking, and we base this hypothesis on the results obtained 



* Xeisser and Friedemann* have noted, it is true, that colloids flocculated by 

 a given dose of salts no longer give such a result if the amount of salt is increased. 

 In their experiments, however, they deal with the salts of heavy metals and they 

 have compared this fact to the formation of colloidal hydrate by hydrolysis of 

 its electrolytes. This evidently is not the case with the salts obtained from red 

 blood cells. 



* Neisser and Friedemann, Miinch. med. Woch., 1904, No. 11. 



