328 Dr. E. T. Hewlett. U> e Effect of the Injection of [June 5, 



RABBIT 1 



RABBIT II 



: - - - 



■O T3 "3 -3 



Chart I. — Opsonic Index after Inoculation 

 -with O'l nigral. Typhoid Endotoxin. 



Chart II. — Opsonic Index after Inoculation 

 with O'l nigrm. Typhoid Endotoxin. 



From the foregoing table it is evident that an injection of O'l milligramme 

 of typhoid endotoxin produces, 24 hours after inoculation, a considerable 

 decrease in the opsonising action of the serum, that is a marked " negative 

 phase " (Wright), followed by a considerable rise in the opsonising action of 

 the serum which persists for some days. The opsonic index yielded by the 

 undiluted serum is given in graphic form in Charts I and II. The dilution 

 of the normal serum produces a decrease in its opsonising action, whereas a 

 dilution of the serum of the inoculated rabbits produces an apparent increase 

 in the opsonising action. 



B. Staphylococcus endotoxin. — Three sets of experiments were carried out 

 with the endotoxin of the 31. pyogenes, var. aureus {Staphylococcus pyogenes 

 aureus), viz., a comparison of the effects of the endotoxin derived from 

 (a) an ordinary old laboratory strain of the organism, (5) a recently isolated 

 strain, and (c) the effect of a vaccine prepared from the strain used for a, 

 on the opsonising action of the serum of normal rabbits. Equivalent 

 quantities (O'l milligramme solid matter) both of vaccine and of endotoxin 

 were given, and the endotoxin solution was prepared with 0'1-per-cent. 

 sodium hydrate solution. The opsonising action of each serum, some time 

 after inoculation, was also tested with both strains of organisms. The 

 results obtained are given graphically in Chart III of the opsonic indexes. 



