496 GENERAL THERAPEUTIC MEASURES 



the poll or spine according to the location of the trouble. Absorption in 

 chronically enlarged glands is ' assisted by blisters. They also hasten 

 "ripening" of suppurating glands or abscess when this process is slow, 

 and hasten their resolution after evacuation of pus. The blister should 

 be rubbed on about the inflamed area in these lesions. 



Vesicants are also valuable in pharyngitis and laryngitis for severe 

 cases, when stimulating liniments are ineffectual; and, in lessening pain, 

 exudation and swelling of the throat, may avert the necessity of trache- 

 otomy. A blister applied about the coronet in diseases of the feet is 

 serviceable in stimulating the growth of the hoof and promotes repair in 

 navicular disease, laminitis, and cartilaginous quittor, after the acute stage 

 is passed. In arthritis and synovitis, the whole diseased area, with the 

 exception of the flexure of the joint, is covered with a blister. Since it 

 is often impossible to immobilize a part, in veterinary practice, by splints, 

 blisters are sometimes employed for this end after reduction of disloca- 

 tions. 



The hair should be clipped from an area to be blistered, the skin 

 washed with soap and water, and the animal tied up or restrained in some 

 way from biting the part. It is the custom to cover immediately the sur- 

 rounding parts with grease, but protection from the acrid discharge can 

 be secured more effectively by frequent sponging with soap suds and 

 water ; or painting the skin, under the blistered surface, with a solution of 

 rosin in alcohol. Grease is not so good a protective, since it is a solvent 

 for cantharides. Vaseline should be applied following the active stage. 



Caustics or Escharotics are agents which destroy tissue. They com- 

 prise such substances as the caustic alkalies, mineral acids, silver nitrate; 

 iron, zinc and copper sulphates ; ferric, zinc and mercuric chlorides ; car- 

 bolic acid, arsenic, together with the actual cautery. They are indicated 

 in the treatment of exuberant granulations, morbid growths, septic, 

 sloughing and necrotic parts, pyogenic membranes, fistulous tracts, and 

 for the destruction of poisons, as in rabid dog and snake bite. Escharotics 

 stimulate and modify nutrition in unhealthy wounds and ulcers. Many 

 form chemical compounds with the tissue elements. Heat oxidizes animal 

 tissues, and also coagulates albumin and abstracts water from them. 



The alkalies produce greasy compounds with the proteids, saponify 

 the fats and withdraw water from the tissues. They are the most widely 

 destructive agents. Silver nitrate forms an insoluble albuminate with the 

 tissues to which it is applied, and protects the underlying structures from 

 further action. It is most superficial in its action, but possesses specific 

 properties in altering the condition of unhealthy wounds for the better. 

 Extreme heat, exemplified by the white-hot iron, acts as a counter-irritant 

 in stimulating reflexly the nervous system; in increasing the vascularity 

 of surrounding parts, and in favoring revulsion of blood ; m aiding absorp- 

 tion and resolution, and in relieving pain apart from its direct destructive 

 effect. Caustics may be applied in either the solid or liquid state, and in 

 various forms, as the stick, powder, paste and ointment. Caustics are 

 sometimes employed to stop hemorrhage. The reader is referred to ar- 

 ticles on special agents for further details. 



Suppurants. — ^Any of the more active counter-irritants, as croton oil, 



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