250 THE FARM DOCTOR. 



Strong glare of sunshine or snow, suddenly hangs on the reins, 

 slackens his pace, staggers a little perhaps, and, if not stopped, 

 drops in harness, first, it may be, starting to one side, or 

 rearing up so as to fall back over the driver. If stopped on 

 the first sign of failing, the attack may usually be warded off. 

 If it has taken place, the loosening of the harness and a few 

 minutes' rest will generally bring the animal round, so that he 

 can get on his legs, but he remains nervous and excitable for 

 several days. 



Prevention. — Treatment.— \x\ plethoric young horses improve 

 the condition by restricted diet and regular increasing exercise, 

 or turn out to grass for a time. Give an occasional laxative 

 and diuretic. Avoid tight or badly fitting collars or whatever 

 presses on the veins of the neck. Shelter the top of the head 

 from the direct rays of the sun by a sunshade. Wear a wet 

 sponge constantly between the ears when at work. When the 

 premonitory symptoms appear, stop, slacken the collar, cover 

 the eyes, apply cold water or ice to the head and neck ; blood 

 may even be drawn from the palate, the temporal artery, or 

 the jugular vein. This should be followed by an active purga- 

 tive (aloes, Glauber salts) and nerve sedatives (chloral-hydrate, 

 bromide of potassium). A laxative diet must be kept up for 

 some time or a run at grass allowed. 



LOCK-JAW. TRISMUS. TETANUS. 



This consists in persistent (tonic) cramps of the voluntary 

 muscles. When confined to those of the face it is t7isnms or 

 lock-jaw, when general tetanus. 



Causes. — Wounds, especially of unyielding structures, like 

 the foot, the firm fibrous layers covering the limbs, shoulder or 

 croup, or the bones (tail). Wounds implicating large sensory 

 nerves, or enclosing rust, gritty matters, or castrating clamps, 

 or subject to chafing as between the thighs, are occasional 

 causes. In other cases exposure to cold or wet, or a continual 



