AGGLUTINATION OF RED BLOOD CELLS. 313 



tion to the fact that red blood cells may be agglutinated by a well- 

 defined colloid, namely, by colloidal silicic acid. Shortly afterward 

 we ourselves* reported examples of agglutination and hemolysis 

 of red blood cells by means of such chemical precipitates as CaFl 2 

 and BaS0 4 . Girard Mangin and Henrif have since studied this 

 question in a very exhaustive and careful manner with different 

 colloids. 



As we have already demonstrated, certain chemical precipitates 

 as well as colloids agglutinate red blood cells, provided the latter 

 are washed free of serum ; this agglutination is followed by hemol- 

 ysis, which latter phenomenon we have referred to in our first article. 

 This agglutination and hemolysis is inhibited by the presence of 

 even very small amounts of serum. 



In the present article we shall consider simply the agglutination 

 of corpuscles and at some later period take up their laking. Mme. 

 Girard-Mangin and V. Henri found that the agglutination of red 

 blood cells is brought about by negative as well as by positive col- 

 loids. Red blood cells, however, have a negative electric charge, as 

 is shown by the fact that they are deposited at the anode. The 

 fact that a negative emulsion (corpuscles) may be agglutinated by 

 equally negative colloids evidently does not coincide with the 

 general ideas that we have gained concerning the action of colloids 

 having effect on one another or other colloids with the same 

 electric charge. A mixture of colloids having the same electrical 

 charge indeed causes no flocculation; both colloids remain in sus- 

 pension, $ and so Mme. Girard-Mangin and V. Henri did not 

 conclude that the agglutination of red blood cells by colloidal 

 substances is due to a direct interaction of these substances. They 

 believe that this agglutination is only an indirect and secondary 

 affair; they think that the corpuscle is passive in the phenomenon 

 and that the active functions are exerted by the colloidal substances 

 on the one hand and by endocorpuscular salts liberated by the cor- 

 puscles on the other. 



It is true, indeed, that certain colloidal substances, as, for example, 

 those studied by Mangin and Henri, are flocculated by electrolytes. 

 When red blood cells are left in normal salt solution they liberate 



* Gengou, Comptes rendus de l'Acad. des Sciences, April 11, 1904. 



t Mme. Girard-Mangin and V. Henri, Soc. de Biol, 1904, Nos. 19, 20, 21, 24, 25. 



% Henri, Lalou, Mayer and Stodel, Soc. de Biol., 1903, Dec. 19. 



