HYGIENE, UNSOUNDNESS, DISEASE. 261 



the tissue of the lung undergoes no material 

 change. The active cause seems to be a de- 

 ranged condition of the pneumo-gastric nerve. 

 Once fairly established heaves are incurable, 

 though the condition of the animal may be ma- 

 terially improved by feeding oats straw in place 

 of hay, and only a little of it, and good bright 

 oats, wetting all food, watering before meals, 

 never afterwards, and permitting a rest of at 

 least an hour after the food is eaten. A little 

 flaxseed jelly fed with the oats is also beneficial 

 and Fowler ^s solution of arsenic does more 

 good than any other drug that may be admin- 

 istered. The use of this remedy should, how- 

 ever, be deferred as long as possible, as its ef- 

 fect is cumulative and it can not be given con- 

 tinuously. An ounce a day is the maximum dose 

 which may be given and it should be tapered off 

 gradually when it is desired to stop. At that, 

 the condition of the horse will not be improved 

 when the effects of the drug have worn off. 

 There are many so-called heave cures. Some 

 will give temporary relief. A permanent cure 

 is an impossibility. 



Whistling or roaring is caused by increase in 

 size of the laryngeal cartilages and the conse- 

 quent diminution of the passage through which 

 the air may be expelled from the lungs. The 

 only possibility of a cure lies in the removal of 

 the distended cartilages by surgical operation— 

 laryngectomy— but that is a most unsatisfac- 



