This name is given to substances which either actually or potentially destroy the living tissue. The actual cautery is an iron heated in the fire, the potential of some chemical substance, such as corrosive sublimate, lunar caustic, caustic potash, a mineral acid, or the like. The actual cautery, or firing, is not often used for the dog, but in some cases it is of great service. Both kinds are used for two purposes: one to relieve the effects of strains and other injuries of the limbs, by which the ligaments are inflamed, and the other to remove diseased growth, such as warts, fungus, etc.

30. - Firing, when adopted for the dog, should be carried out with a very small thin-edged iron, as the dog's skin is thin, and very liable to slough. No one should attempt this without experience or previously watching others.

31. - Lunar caustic, or nitrate of silver, is constantly required, being very manageable in the hands of any person accustomed to wounds, etc.

32. - Sulphate of copper, or bluestone, is much milder than the lunar caustic, and may be freely rubbed into the surface of fungus or proud flesh. It is very useful in ulcerations about the toes.

33. - Fused potass is not fit for any one but the experienced surgeon.

34. - Corrosive sublimate in powder may be applied, carefully and in very small quantities, to warts, and then washed off. It is apt to extend its effects to the surrounding tissues.

35. - Yellow orpiment is not so strong as corrosive sublimate, and may be used in the same way.

36. - Burned alum and white sugar, in powder, act as mild caustics.