252 PKINCIPLES OP VETERINARY SCIENCE 



Local anesthetics are employed when the part operated upon is 

 limited in area. General anesthetics produce a loss of conscious- 

 ness, sensation, and motion. The muscles relax and the patient 

 lies motionless when anesthesia is complete. It should be under- 

 stood that accidents and dangers attend general anesthesia of the 

 horse. Chloroform and ether are the chief anesthetics used. 

 Either of these may be given while the horse is standing, by means 

 of a "mask" or "inhaler" that slips over the muzzle and straps 

 around the face. More often the animal is thrown, one nostril is 

 plugged with cotton, and he is made to inhale the fumes of the 

 anesthetic through gauze stretched across the other nostril. 

 From 3 to 6 ounces of chloroform, given over a period of some 

 twenty minutes, are necessary to place the horse fully under its 

 influence. Chloral hydrate has many advantages as a narco- 

 tizing agent. It is given in aqueous solution either intravenously 

 or by the mouth. The dose varies from 20 to 70 grams. Cocain 

 is the most popular agent for producing local insensibility to pain. 

 It is injected hypodermatically over the nerves of the part to be 

 operated upon. As a means of finding the exact seat of lameness 

 it is especially valuable. 



SLINGING 



Slings are useful to support the animal in the standing position 

 when he is unable to stand without assistance. If the horse 

 refuses to assist himself and hangs in the slings they should not be 

 used. 



There are a number of different types of slings on the market. 

 The older makes have a wide canvas girth, which passes under the 

 body and presses on both the sternum and the abdomen. They 

 are objectionable for the reason that too much pressure is brought 

 to bear on the abdomen when the horse throws his weight into the 

 slings. With pregnant mares this is a decided disadvantage, as it 

 may result in abortion. In any case, the abdominal viscera are 

 pushed forward and press on the diaphragm, which, in turn, com- 

 presses the lungs and interferes with respiration. 



The newest type of sling is so constructed that the weight is 

 borne by a relatively narrow girth and breast-piece, which press 

 only on the sternum and pectoral muscles, and has a breeching in 

 which the horse may rest the hind quarters with safety and com- 

 fort. All the parts of a good sling should be adjustable by means 



Digitized by Microsoft® 



