386 THE HORSE. 



libejuieo, ihc ball is forced through the pharynx into the ajsophagus. Its 

 passage should be watched down tiie left side of the throat; and if it ia 

 not seen going down, a sliglit tap or blow under the chin will generally 

 •cause the horse to swallow, or a few gulps of water will carry it down. Jf 

 the gullet should be small or strictured, and the ball should remain in some 

 part of it, the method of removing it has been described in page 162. 



Blisters are applications to the skin which separate the cuticle in the 

 form of vesicles containing a serous fluid. They excite increased action in 

 the vessels of the skin, by means of which this fluid is thrown out. The 

 part or neighbouring parts are somewhat relieved by this discharge, but 

 more by the inflammation and pain wliich are produced, and which lessen 

 the inflammation and pain previously existing in some contiguous part. 

 On this principle we account for the decided relief often obtained by 

 blisters in inflammation of the lungs; their efficacy in abating deeply- 

 seated inflammation, as that of sprain of the tendons, ligaments, or joints; 

 and the necessity of removing first, in these latter cases, the superficial 

 inflammation caused by the sprain, tiiat inflammation of a different kind 

 may be excited instead of it, to which tlie deeply-seated inflammation of the 

 part will be more likely to yield. The blisters used in horse-practice are 

 composed only of cantharides or the oil of turpentine, to which some have 

 added a tincture of the croton-nut. The method of forming the best 

 blister is mentioned at page 186. 



Bole Armenian is an argillaceous earth combined with iron, and ia 

 supposed to possess some astringent property. The propriety of its 

 being best administered inwardly is doubtful; for it may remain in the 

 intestinal canal, and become the nut of a stone. On account of its supposed 

 astringency, it is employed externally to give consistence to ointments 

 for grease. Even the bole Armenian has not escaped the process of 

 adulteration, and is largely mixed with inferior earths. The fraud may 

 be suspected, but not satisfactorily detected, by the colour of the powder, 

 which should be a bright red. 



Burgundy Pitch. — See Resin. 



Calamine. — See Zinc. 



Calomel. — See Mercury. 



Camphor is the produce of one of the laurus species, a native of Japan, 

 and is imitated by passing a stream of chlorine through oil of turpentine. 

 The efficacy of this drug when used internally is very doubtful. The 

 camphor ball is a favourite with the groom, and occasionally administered 

 by the veterinary surgeon, but, seemingly, with no definite object, for it 

 has not been yet determined whether it is to be considered as a sedative, 

 anti-spasmodic, or stimulant. It is, however, a stimulant, when applied 

 externally. In the form of camphorated oil, it promotes the absorption of 

 fluids thrown out beneath the skin, the removal of old callus, and the 

 suppleing of joints stitf from labour. Combined witii oil of turpentine it is 

 more efl'ective, but in that combination it occasionally blemishes. 



Cantharides are the basis of the most approved and useful veterinary 

 blisters. The cantharis is a fly, the native of Italy, and the south of 

 France, destroyed by sulphur, dried and powdei'ed and mixed with palm 

 oil and resin, in the proportions directed at page 186. Its action is 

 intense, and yet superficial; it plentifully raises the cuticle, but never 

 injures the true skin, and therefore never blemishes. The application of 

 other acrid substances is occasionally followed by deep-seated ulcerations; 

 but a blister, composed of the Spanish fly alone, whiie it does it-= duty, leaves, 

 after a few weeks have passed, scarcely a trace behind. The art of 

 blistering consists in cutting, or rather shaving the hair pertoctly close — 



