Bacilli only. Bacilli; sporulating bacilli; free spores. Multiplies freely in blood stream. Dies in blood stream unless charged with toxins. Rabbit very susceptible; man less Rabbit, pigeon and man immune. so. Produces no gas. Gas producing. Inoculation swelling very Inoculation swelling very restricted. extensive. Bacillus destroyed by Not destroyed by putrefaction. putrefaction. _Resistance of bacillus of black quarter to physical and chemical agents._ The microbe is possessed of great vitality. Thoroughly dried at a temperature of 95° F. it retains its virulence. The spores may be preserved indefinitely in dry soil, buildings, fodder, litter, harness, etc. Cold is equally harmless to it. It has been exposed to a temperature of 98° F. below zero without losing its virulence. Its virulence is lessened by exposure for an hour to 139° F., and it is sterilized at a temperature of 212° F. for twenty minutes. The dried spores are virulent after six hours of the boiling temperature but are sterilized at 230° F. if maintained for the same length of time. Diffused in water the virus is sterilized in thirty-five minutes at the boiling temperature. Some waters at ordinary temperatures destroy the virulence in twenty-four hours; others not for many months. It is destroyed by the more potent disinfectants, mercuric chloride (1:1000), silver nitrate (1:100), acid salicylic (1 to 2:100), acid carbolic (2 to 4:100), copper sulphate (20:100), boric acid (20:100), muriatic acid (1:2). Quicklime, copperas, zinc chloride, sulphuric acid and an alcoholic solution of phenol have proved unsatisfactory. In clay soils, hard pans, waterlogged soils, and in some that are over manured so that the atmospheric air is excluded, it may be preserved indefinitely. Feser, Gotti and others have produced the disease by inoculating with the washings of infected marshy soils, and this is doubtless a common source of casual cases of the malady.