80 Tlie Farmer's Veterinary Achiser. 



tage of showing clearly the extent of its application, insur- 

 ing that no part shall be missed, and thus it becomes even 

 a more certain disinfectant than the more potent salt of 

 mercury. As a powder it may be sprinkled on floors, 

 yards, manure-heaps, and in drains, cess-pools, etc. 



For dairies, in which the smell of the chloride of lime 

 will injure the milk, chloride of zino may be substituted. 



Chlorine gas, set free by pouring sulphuric acid on com- 

 mon salt, with a slight admixture of black oxide of man- 

 ganese, is one of the most effective purifiers of the air of 

 buildings. Doors and windows should be closed, though 

 light is beneficial to its action. The salt and black manga- 

 nese should be placed in a bowl in the centre of the floor, 

 and the operator, taking a full breath, should pour in the 

 sulphuric acid and retreat outside the door befoi'e taking 

 another breath. The gas is a violent and suffocating irri- 

 tant, and if inhaled is promptly fatal. 



Sulphurous acid gas, obtained by burning sulphur in a 

 metal pot, may be fairly started, then left in the centre of 

 the room and all outlets closed for from five to ten hours. 

 The same precautions are necessary as with chlorine, for 

 though it is somewhat less irritating it is equally suffocating. 

 Both gases will act on solids as well as on the air, and to 

 make sure of their action the air and surfaces should be 

 charged with moisture. Perfectly dry germs will often 

 survive, whereas moist ones are quickly destroyed. Hence, 

 a current of steam may be sent into the building, or all 

 exposed surfaces may be watered before the gas is set free. 



Some disinfectants act by merely changing the physical 

 condition of organic matter, and thereby desti-oying the 

 vitality of the living germ, without any chemical abstraction 

 from, or addition to, its constituents. Thus heating to the 

 boiling-point (212° F.) coagulates albuminous matters and 

 destroys infectious principles generally. But it must be 

 prolonged for a variable time, according to the size of the 



