PROTECTIVE INOCULATIONS. o43 



are said not to have acquired any immunity against the toxins of the 

 micrococcus of pneumonia. Contrary to the conclusion reached by 

 G. and F. Klemperer, Issaeff concludes from his experiments that 

 "rabbits, although completely refractory against pneumonic infec- 

 tion, remain highly sensitive to the toxins of this microbe. Even 

 small doses of the toxins are not neutralized in the blood of vacci- 

 nated animals. We are therefore brought to the conclusion that the 

 existence of an antitoxic property of the blood of vaccinated animals 

 cannot be admitted." 



The serum of immunized rabbits was not found by Issaeff to pos- 

 sess any bactericidal power for the micrococcus of pneumonia, and 

 no attenuation of virulence occurred as a result of cultivation in this 

 serum. But when introduced beneath the skin of an immune rabbit, 

 the micrococcus quickly loses its virulence. At the end of eighteen 

 hours it has completely lost its pathogenic power, and cultures made 

 in bouillon no longer have any injurious effect upon rabbits. This 

 attenuating effect produced in the body of an immune animal is 

 ascribed by Issaeff to the action of phagocytes, which are said to be 

 very numerous, and in the course of five or six hours to pick up all of 

 the cocci in the vicinity of the point of inoculation. These are not, 

 however, immediately destroyed in the interior of the phagocytes, but 

 preserve their vitality for nearly forty -eight hours, and when intro- 

 duced into bouillon give a culture which has no longer any patho- 

 genic virulence. 



RINDERPEST. 



The disease of cattle known in Germany as rinderpest is due to a 

 bacillus closely resembling the bacillus of fowl cholera and of swine 

 plague (BaciUus septiccemice hcemarrhagicce). 



Professor Semmer, of St. Petersburg, has reported (1892) his suc- 

 cess in immunizing cattle against this disease. The virulence of cul- 

 tures was attenuated by passing them through guinea-pigs, or by 

 exposure to heat, and this attenuated virus was used in protective 

 inoculations. Semmer says : 



"By the subcutaneous injection of blood serum from immune animals 

 their susceptibility to rinderpest was diminished, and such blood serum de- 

 stroyed the 'rinderpest contagium' in one to twenty-four hours/' 



SWINE PLAGUE. 



As stated in the chapter on cholera in fowls, the bacillus of swine 

 plague (ScJnveineseuche, Loftier and Schiitz) very closely resembles 

 Pasteur's microbe of fowl cholera and Koch's bacillus of rabbit sep- 



