MOUSE-SEPTICEMIA. 333 



rabbits. Two vaccinations are said to be necessary to 

 produce immunity. The vaccinated animals, however, 

 may be a source of infection to others, and should always 

 be isolated. Klemperer in 1892 found that the blood- 

 serum of immunized rabbits would save infected mice 

 into which it was injected. 



L,orenz in 1894 found an antitoxic substance in the 

 blood of rabbits immunized to the disease. The effect 

 of its injection into other animals is, however, only a 

 temporary immunity. 



