26 QUATERCENTENARY STUDIES IN PATHOLOGY 



In the investigation of this question, sera from several sources were 

 examined, serum from pneumonia patients at the crisis with high 

 opsonic index, serum from a patient suffering from acne vulgaris who 

 had been treated with injection of staphylococcus vaccine, and sera of 

 rabbits actively immunised against staphylococcus and against pneumo- 

 coccus. 



Sera from each of these sources gave the same reaction towards 

 physical agents. They shall be designated " Immune sera." 



The only great difference in the behaviour of immune sera and normal 

 sera towards chemical and physical influences is in relation to the effect 

 of heat. Heating to 60° destroys 80 to 90 per cent, of the opsonising 

 power of normal serum. In immune sera heat does not exert such a 

 great influence. 



The serum of a patient who had received repeated injections of 

 staphylococcus albus was tested. His opsonic power, with relation to a 

 normal individual, was i*8. This was subjected to heat for 30 minutes. 



1. Control serum i4'8 



2. Patient's serum ------- 237 



3. No. I heated to 60° for 30 mins. - - - - 2*9 



4. No. 2 II ----- 6*9 



From this experiment the opsonin does not seem to be destroyed to 

 such an extent by heat. Is the residue in the serum of the nature of 

 opsonin, or is it another substance ? 



If it is opsonin, then it would be able to opsonise fresh cocci passed 

 through it. To demonstrate this, several experiments were performed of 

 which a type may be cited. 



Immune serum and normal serum were heated to 60° C. for 30 min., 



the thermolabile opsonin being thereby destroyed. To the heated sera 



were then added equal parts of an emulsion of staphylococcus, and the 



mixtures were digested at 37° C. for 30 minutes. At the end of this time 



the mixtures were centrifuged, the supernatant liquid and the cocci 



being separately tested with the following result : — Cocci per 



leucocyte. 



1. Heated normal serum 2*9 



2. Heated immune serum ------- 6*9 



3. Supernatant fluid after digestion with normal heated serum - 0*9 



4. Supernatant fluid after digestion with immune heated serum 6'o 



5. Cocci after digestion with normal heated serum - - - 2*3 



6. Cocci after digestion with immune heated serum - - 2-1 



(390) 



