OPSONIC ACTION 177 



Treatment by Precipitate 1 



Opsonic count 



Anti-staphylococcus serum 



Heated at 55 C 7-2 



Heated and treated with precipitate . . . 7-0 



Normal serum 



Unheated . . . . . ; . . 24-6 



Unheated and treated . .".' * 0-86 



Treatment by Red Corpuscles + Immune-Body 



Opsonic count 



Anti-staphylococcus serum 



Heated at 55 C. . ' . ... .' V 8-3 

 Heated and treated 94 



Normal serum 

 Unheated . . . . . . . . . . 20-8 



Unheated and treated . . . . . .'0-8 



The thermolabile opsonin of the normal serum is absorbed, 

 whereas the thermostable opsonin of the immune serum 

 is unaffected. 



Treatment by Emulsion of V. Metchnikovi + Immune- 



body 



Opsonic count 

 Anti-staphylococcus serum 



Heated at 55 C 17-2 



Heated and treated 17-5 



Normal serum 



Unheated 25-0 



Unheated and treated . . . . . .2-36 



The result is the same as before. 



We have also endeavoured to remove the opsonin of the 

 immune serum by treating it twice with a considerable 

 quantity of serum precipitate, the precipitate being separ- 

 ated by centrifugalization after each treatment, but no 

 diminution of the opsonin has resulted. The following is 



1 In this and the two following experiments the anti-serum was the one 

 which we obtained from Dr. Dean. 



2IUIB 



