BPFECT OF HEAT ON OPSONIN. ."/ 



Wright has based a method for the diagnosis of certain microor- 

 ganisms in infections. This can, however, only be regarded as 

 logical if opsonins are specific. Bulloch and Western found that 

 in normal serum, by absorption tests, the specificity of opsonin 

 for B. pyocyaneus, B. tuberculosis and staphylococci could be 

 determined. Muir and Martin, Simon, Russell, Potter, Dittman 

 and Bradley, and others, have found that normal opsonins are 

 not specific. Muir and Martin, and Russell, however, by absorp- 

 tion tests have determined that immune opsonins are quite spe- 

 cific. vSimon, however, has not been able by investigation to 

 prove the existence of specific immune opsonin. 



EFFECT OF HEAT ON OPSONIN. 



Wright has consistently assumed that normal and immune 

 opsonins are identical and has preferred to regard all opsonins 

 as thermolabile. There are, however, on the other hand, a large 

 group of observations which show that while opsonins in immune 

 serum resist a temperature of 55 C. for one hour, opsonins in 

 normal serum will no longer be able to prepare bacteria for phag- 

 ocytosis by the leucocytes after such an exposure to heat. These 

 observations show plainly that immune opsonin is thermostable, 

 while normal opsonin is thermolabile. The basis for Wright's 

 assumption that they are all thermolabile is not evident, inas- 

 much as Wright and Reid have shown that in the serum of cer- 

 tain patients suffering from tuberculosis there is a thermostable 

 opsonin. On this observation Wright has based a method for 

 the diagnosis of tuberculosis, which can only have for a founda- 

 tion the assumption that in tuberculosis specific immune bodies 

 which are heat resisting, are produced. From the various inves- 

 tigations reported, normal and immune opsonins manifest a marked 

 difference in ability to withstand heat. 



STRUCTURE OF OPSONINS. 



Opsonins have, by numerous investigators, Savtchenko, 

 Besredka, Loehlein and Dean, been regarded as identical with 

 amboceptors (fixateur). Muir and Martin have shown that not 

 every immune body produces an opsonizing effect. Hektoen has, 

 from a series of experiments, decided that opsonins are distinct 

 substances or anti-bodies. Neufeld and Rimpau, Neufeld and 



