458 PA THOGENIC BA CTERIA. death in the presence of oxygen. This is, however, un- true, for the rapid development of a permanent form in the resisting spores of the bacillus makes the pollution of the soil exceedingly dangerous for cows who subse- quently browse upon it. That the spores are of great vitality is shown by the well-known laboratory method of keeping them on hand for experimental purposes, dried in the muscular tissue of a diseased animal. Every precaution should be exerted to have the affected animals isolated, and their cadavers disinfected and de- stroyed or buried in such a manner that subsequent infection is impossible. Statistical results of Guillod and Simon, based upon 3500 protective inoculations, show a distinct reduction of the death-rate from 5-20 per cent, in unprotected animals to 0.5-2 per cent, in protected animals.