24 QUATERCENTENARY STUDIES IN PATHOLOGY 



two parts of serum and one part of different strengths of salt solution, 

 and then subjected to 55° C. for varying periods. 



In the experiments with 2 % and 5 "/^ NaCl. the opsonin seemed to 

 be entirely destroyed by heating for five minutes to 55° C. 



Far from preserving the opsonin from destruction by heat, the 

 increasing concentration of salt seems to favour its destruction very 

 greatly. 



The work of Wright and Douglas, corroborated also by Bulloch and 

 Atkin, has shown that the opsonin disappears from the serum when the 

 serum is digested with bacteria at 37° C. or at 0° C. We have seen that 

 serum heated to 60° C. for some time loses the great part of the opsonin 

 present. Is this really a destruction of the opsonin, or does it pass into a 

 modification (opsonoid), in which it does not fully prepare the bacteria 

 for phagocytosis? Can a complement-like body be isolated as in 

 haemolysis at 0° C. which would give a reaction with heated serum ? 



An emulsion of staphylococci (pneumococci gave a similar result) was 

 added to normal serum and digested for 30 minutes at 0° C. The 

 centrifuge was then applied, and a supernatant clear fluid obtained with 

 a deposit of staphylococci. Serum was also heated to 60° C. for 30 

 minutes. 



(388) 



