270 



SPECIFICITY OF OPSONINS 



by diminishing the viscosity of the blood by the exhibition of 

 citrates and other anticoagulants, by the use of hot applications, 

 and by Bier's method of congestion. 



The first point which arises in a discussion of the opsonic 

 theory deals with the specificity of the opsonins themselves. Are 

 we to imagine that there is a specific opsonin to each organism, 

 and that during the process of immunization this increases, 

 whilst the others remain constant ? Unless this is the case, the 

 theory fails, for we know that immunity is specific. 



101 

 100 

 99 



2-5 



1-5 



Day 

 7 8 



$ 10 II 12 13 



FIG. 63. BEHAVIOUR OF THE OPSONIC INDEX IN A MILD (a) AND SEVERE 

 (6) CASE OF ERYSIPELAS. (After Tunnicliffe. ) 



The latter shows the preagonal rise ; the broken line in the first chart 

 indicates the temperature. 



The question may be investigated in two ways by absorption 

 of the opsonins and by comparison of different sera. 



The first method was employed by Bulloch and Western, who 

 added an emulsion of tubercle bacilli to normal serum, and found 

 but a slight reduction of the opsonic index to staphylococci, 

 suggesting the difference of the two opsonins. But these 

 results have not been confirmed by later writers, and it is quite 

 certain that a sufficient amount of tubercle bacilli will remove 

 practically the whole of the opsonin to staphylococci. These 

 experiments tend, therefore, to show that the opsonins are not 



