234 OMENTAL PLAGUE chap. 



some active germicidal substance, although in a small 

 amount. 



(3) August 10. — Guinea-pig No. 26 was injected with 

 a mixture of 100 cubic millimetres of emulsion and 100 

 cubic millimetres of blood serum. At the same time 

 guinea-pig No. 27 was injected with 100 cubic milli- 

 metres of emulsion alone. 



The control guinea-pig No. 27 died of plague on the 

 sixth day, the other guinea-pig, No. 26, died of plague 

 on the seventh day. This experiment does not denote 

 the presence of germicidal substance in the blood of 

 guinea-pig No. 1, even when serum and plague emulsion 

 have been injected in equal amount. 



The guinea-pig No. 1 had been injected on September 

 16, a thirteenth time, this time with a double dose of 

 living gelatine culture. On October 17 the animal was 

 killed, and it showed nowhere any pathological appear- 

 ances. As already mentioned, its blood serum at this 

 stage gave on agglutination test (dilution 1 : 20) 

 completely positive result in ten minutes. Its blood 

 serum, as also a salt extract of the spleen (this organ 

 looked quite normal), were now used in the following 

 manner : — 



(1) 200 cubic millimetres of plague emulsion were 

 mixed with 200 cubic millimetres of blood serum, and 

 the mixture injected into guinea-pig No. 40. 



(2) 200 cubic millimetres of plague emulsion were 

 mixed with 50 cubic millimetres of blood serum, and the 

 mixture injected into guinea-pig No. 39. 



(3) 200 cubic millimetres of plague emulsion were 

 mixed with 200 cubic millimetres of thick spleen emulsion, 

 and the mixture injected into guinea-pig No. 41. 



