OPSONIC INDEX AND VACCINE THERAPY 335 



ordinary normal conditions they would fall prey to phagocytic de- 

 struction soon after entering the body. 



The study of the opsonic index during the treatment of such 

 cases with dead staphylococcus cultures (usually with the organisms 

 cultivated from the patient's own lesions " autogenous vaccines") 

 revealed a striking coincidence between the rise of the opsonic index 

 and improvement in the clinical conditions. A number of further 

 interesting and practically important points were brought out by 

 the systematic study of these relations which may be illustrated by 



5% 6 7 s 9 /o//l^/3/4/5/6/7/8/920^/^^Z5^4&^t^ 



CURVE I. EESULT UPON OPSONIC INDEX OF VACCINE TREATMENT IN Two CASES OF 



CHRONIC STAPHYLOCOCCUS FURUNCULOSIS. 



(After Wright and Douglas, Proc. Royal 8oc., Vol. 74, 1904, p. 156; also from 

 "Studies on Immunity," p. 41.) 



reproducing a plan of the opsonic index curves constructed from 

 cases. 



The curve shown above, and taken from a paper by Wright and 

 Douglas, illustrates the course of the opsonic fluctuations in the 

 case of a medical student who had suffered for four years from boils. 



When first seen the opsonic index (1. being normal) was 0.6, 

 and there were 2 boils on the neck. For 3 days after this there was 

 a spontaneous rise in the index accompanied by an improvement of 

 the lesions. 



On the third day 2 billion staphylococci were injected. This 

 was followed by an immediate drop of the phagocytic power (the 

 negative phase) ; together with this a new boil began to form. Soon, 

 however, the opsonic power began again to rise, this time consid- 

 erably above normal, reaching its highest point on the 8th day, when 



