23 
stronger. It is further proved by our immunity against another 
c 
disease. Or, if the indi ee has not yet contracted the disease, 
he can be prevented from doing so upon inoculation of the pois- 
of as ee fluid from the bodies of convalescent human 
which they have grown, but in which they have been destroyed, 
or from which they have been filtered out. Only a very small 
ee can be safely introduced at first, but as the system of the 
ntil sufficient to have killed many untreated horses can be safely 
