1909.] 



Intracellular Constituents of Bacteria, etc. 



329 



RABBIT III 



RABBIT IV 



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RABBIT V 



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Chart III. — Staphylococcus Vaccine and Endotoxins. 



Rabbit III received 1 c.c. (= 1000 x 10 6 = 0"1 milligramme) Staphylococcus Vaccine. 

 Rabbit IV received - l milligramme Staphylococcus Endotoxin, old strain. 

 Rabbit V received - l milligramme Staphylococcus Endotoxin, new strain. 



Main trace = index determined with old strain of Staphylococcus. 



Small upper trace = index determined with new strain of Staphylococcus. 



It will be seen from these experiments that the endotoxin prepared from 

 the old laboratory strain (Eabbit IV) gave nearly as marked a rise in the 

 opsonic index as the vaccine (Eabbit III), but that the former seems to 

 induce less negative phase than the latter, and its effect is more per- 

 sistent. The endotoxin prepared from the recently isolated strain (Eabbit V) 

 induced a rise in the opsonic index much more marked than that induced by 

 either the vaccine or the endotoxin prepared from the old laboratory strain. 

 The sera, some time after inoculation (two to seven weeks), tested against the 

 recently isolated strain, gave an opsonic index slightly higher in the case of 

 the vaccine (Eabbit III) and much higher in the case of the endotoxins 

 (Eabbits IV and V) than that obtained when tested against the old laboratory 

 strain. 



The effects of different amounts (0 - l, O'Ol, O001 milligramme) of another 

 freshly prepared staphylococcus endotoxin solution were also tested, and the 

 results are given graphically in Chart IV of the opsonic indexes, and are 



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