224 Veterinary Medicine. 



Resistance of bacillus of black quarter to physical and chemical 

 agent. 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, fod- 

 der, 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 is sterilized at a temperature' of 212° 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 (i : 1000) , silver nitrate 

 (i : 100) , acid salicylic (i to 2 : 100) , acid carbolic (2 to 4 : 100), 

 copper sulphate (20 : 100) , boric acid (20 : 100) , muriatic acid 

 (i : 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. 



Accessory causes are important. The predisposing influence of 

 la:ctic acid, of other organic acids, and of overwork have been 

 already named. Potass salts, alcohol, common salt and the pro- 

 ducts of proteus vulgaris, or micrococcus prodigosus increase the 

 susceptibility. I^ow condition, debility, or suddenly induced 

 plethora have a similar influence. Sudden changes of weather, 

 chills, and particularly the access of hot weather in spring, when 

 the animal is changing its coat lays the system open to attack. 

 Youth, after the period of suckling, and under three years old, 

 seems to increase the predisposition, though this is largely the 

 result of the absence of a previous exposure. Then impermeable, 

 clay, wet, marshy soils, or those charged with organic matter are 

 conditions of the presence of the microbe. It often appears in 

 spring in connection with the melting of the winter's snows, the 



