238 ORIENTAL PLAGUE chap. 



with Haffkine's prophylactic, furnished blood serum which 

 was tested for germicidal effects after the fourth and 

 again after the seventh injection. The result was in 

 both instances quite negative. 



In the face of these results I have not thought it 

 expedient to test the blood serum of the guinea-pigs 

 which had been injected with the filtrate alone of 

 Haffkine's prophylactic. 



(b) Babbits. — The blood serum of the following three 

 protected rabbits was submitted to the germicidal test, 

 namely : — 



Rabbit No. 1, referred to at p. 220 as having been 

 intravenously injected at first (three times) with sterile, 

 then (twice) with small doses of living culture ; rabbit 

 No. 3, referred to at p. 222 as having been repeatedly 

 injected subcutaneously with Haffkine's prophylactic ; 

 and rabbit No. 5, referred to at p. 223 as having been 

 repeatedly iujected, first intravenously and then sub- 

 cutaneously, with Haffkine's prophylactic. 



Rabbit No. 1. — Test of this rabbit's serum was made 

 on July 16, that is to say, one week after the fourth 

 intravenous injection. 



(1) 100 cubic millimetres of plague emulsion mixed 

 with 50 cubic millimetres of the blood serum were injected 

 into guinea-pig No. 13. 



(2) 100 cubic millimetres of plague emulsion mixed 

 with 100 cubic millimetres of the blood serum were in- 

 jected into guinea-pig No. 14. 



The result was negative ; both animals died of 

 plague, No. 13 on the sixth day, No. 14 on the seventh 

 day. 



Rabbit No. 3. — The blood serum of this rabbit was 



