74 Messrs. Dudgeon and Wilson. On the Presence of [Sept. 11, 



After the serum had been saturated with the red cells in the manner 

 described for 15 minutes at 37° C, the following result was obtained : — 



The " serum " + normal leucocytes (R) + Stajjhijlococcus aureus, 

 50 cells = 94 cocci. 



In this experiment it was shown that L.'s serum had a powerful hpemolytic 

 action on E.'s red cells, and we find as a result of saturating this serum with 

 these red cells that there is a reduction of phagocytic activity from 270 to 94 

 in so short a time as 15 minutes. A control experiment conducted with 

 E.'s serum and E.'s leucocytes showed 155 cocci in 50 cells before saturation, 

 and 148 following saturation, while with E.'s serum and D.'s leucocytes 

 176 cocci were engulfed, and subsequent to saturation 168 cocci — in both 

 these experiments neither haemolysis nor haim-agglutination occurred. We 

 have here, therefore, an instance of a certain normal serum which is markedly 

 ha^molytic for normal red blood corpuscles, and in which greatly reduced 

 phagocytosis could be demonstrated by saturating it with these red cells for 

 15 minutes. It must be pointed out here, however, that in some instances, 

 although haemolysis occurs, thei'e is no striking decrease in phagocytosis when 

 the serum is satuiated witli suitable red cells for a period of 15 minutes at 

 37° C. It can also be stated, as a result of a very large number of obser- 

 vations, that a reduced phagocytosis is entirely related to haemolysis, and is 

 unaffected by the presence of htem-agglutinins. Similar results can be shown 

 when an immune serum acts in the presence of normal leucocytes. In the 

 experiment to be recorded tlie innnune serum had a powerful luiimolytic 

 action on the normal red cells. 



Immune serum + normal leucocytes + Staphi/lococr.us aareus, 

 50 cells = 388 cocci. 



The serum was saturated witli the normal red cells foi' 15 minutes at 

 37° C, and then centrifugalised at high speed. When tlie serum, after 

 saturation, was added to the same leucocytes and cocci, 50 cells contained 

 146 cocci. In a control experiment witli the normal serum and normal 

 leucocytes obtained from the saiiK! iiidivithial, in which tliero was an absence 

 of haemolysis, there was only a very slight reduction in phagocytosis. 



In the next expei-iment the immune sei-um from one case was allowed to 

 act in the pi'cseiice of imnuine red cells of another. 



IinnuiiK! Hcrum (A) + imnuine leucocytes {\\) + J>'. coil, 

 50 cells = 249 bacilli. 



