ON THE NATURE OF OPSONINS. 393 



between Ehrlich and Sachs* on the one hand and Bordet and Gayf 

 on the other in regard to the explanation of the phenomenon of 

 complement deviation. We do not wish here to enter into this 

 theoretical controversy, but merely mention the fact that the bring- 

 ing of diluted washed guinea-pig blood in contact with inactivated 

 bovine serum and fresh horse serum in suitable quantities produces 

 rapid and very pronounced agglutination (later hemolysis) , for which 

 phenomenon the alexin of the horse serum is necessary. 



We now setup two tubes (a and b), each of which contains 0.2 of 

 a cubic centimeter of physiological saline solution and 1 drop of 

 a 1-10 dilution of washed guinea-pig blood and half a drop of in- 

 activated bovine serum. To mixture "a" is added a drop of the 

 liquid from the tube "A," while, to the similar mixture "b," 

 1 drop of the liquid from tube "B" is added. In mixture "b" 

 the blood corpuscles are distinctly agglutinated in about 10 minutes. 

 In "a" the agglutination is totally absent and remains so. Fluid 

 "B " contains, therefore, free alexin; "A," however, does not. 



Let us inquire, now, what the condition of the opsonic power of 

 these two fluids is. For this purpose the mixtures indicated are 

 prepared, using in each case equal quantities of the several com- 

 ponents (1 drop of each in a hollow ground slide protected from 

 the air by a cover glass). After a contact of 30 minutes smears 

 are prepared. The account of one of my experiments gives the 

 following results: 



1. Washed frog leucocytes 



An emulsion of anthrax bacilli [ Result, no phagocytosis. 

 Physiological saline J 



2. Washed frog leucocytes 1 OD . ,, , , 

 Emulsion of anthrax bacilli 2b P er ce " t . of the leucocytes counted 

 Fluid from tube "A" engaged in active phagocytosis. 



Anthrax bacilli 1 ^ P er cen ^ °^ ^ ne leucocytes show 



Fluid from tube "B" J phagocytosis. 



4. Leucocytes 



Emulsion of typhoid bacilli [ Minimal phagocytosis. 

 Physiological saline solution 



5. Leucocytes 19 per cent of the counted leucocytes 

 Emulsion of typhoid bacilli [ are more or less filled with typhoid 

 Fluid "A" J bacilli. 



6. Leucocytes 1 ao c ,, , , 

 Emulsion of typhoid bacilli 83 P er ce f . of the leucocytes show 

 Fluid "B" phagocytosis. 



* Studies on Immunity, Ehrlich-Bolduan, John Wiley and Sons, p. 209. 

 t See p. 363. 



