GERMICIDES AND ANTISEPTICS. 227 



Ozone impairs, and, if maintained long in con- 

 tact, destroys the activity of vaccine lymph (Braid- 

 wood and Vacher). All germs suspended in the 

 air, capable of developing in solutions of yeast 

 from beer, are killed by ozone (Chappuis). 



Oxygen. The experiments of Pasteur upon the 

 attenuation of virus show that long exposure to 

 the oxygen of the atmosphere reduces the repro- 

 ductive activity of the micrococcus of fowl-cholera 

 and of the anthrax bacillus, and that after a time 

 the vitality of these organisms is destroyed. The 

 spores of the anthrax bacillus are, however, un- 

 affected by prolonged exposure. Out of twelve 

 experimental vaccinations with vaccine exposed to 

 oxygen (time of .exposure one to seven days), but 

 one was successful, and in this case there is reason 

 to believe that the exposure was imperfect (Braid- 

 wood and Vacher). 



Picric Add prevents the development of the 

 spores of bacilli in the proportion of 1 : 5,000 

 (Koch). The development of bacteria in beef- 

 infusion is prevented by 1 : 2,005, and the bacteria 

 of broken-down beef-tea are destroyed by 1 : 100 

 (de la Croix). 



Potash. Caustic potash in the proportion of 

 two per cent was fatal to the micrococcus of sep- 

 ticaemia in one experiment, and failed in another ; 

 eight per cent failed to kill the micrococcus of pus, 

 while ten per cent was successful ; ten per cent 

 failed to destroy the bacteria in broken-down beef- 

 tea, and twenty per cent was successful (S). " Caus- 



