90 



Tlie sinuses of the head are compartments which communicate with 

 tlie nasal chambers and are lined with a continuation of the same 

 membrane that lines the nasal chambers; their presence increases 

 the volume and modifies the form of tlie head without increasing its 

 weight. 



The horse, in a normal condition, breathes exclusively through tlie 

 nostrils; no air passes through the mouth in respiration. This is 

 one reason why horses probably are affected oftener with colds than 

 other animals. The organs of respiration are more liable to dis- 

 ease than the organs connected with anj' other function of the animal, 

 and, as many of the causes can be prevented, it is both important and 

 I)rofitable to know and study the causes. The respiratory surface in 

 the lungs of the horse is estimated to be from 200 to 500 square feet. 



The cause of many of the diseases of these organs may be given 

 under a common head, because even a simple cold, if neglected or 

 badl}^ treated, may run into the most complicated lung disease and 

 terminate fatally. In the spring and fall, when the animals are 

 changing their coats, there is a marked predisposition to contract 

 disease, and consequently care should be taken at those periods to 

 prevent other exciting causes. 



Badly ventilated stables are a frequent source of disease. It is a 

 great mistake to think that country stables necessarily have purer air 

 than city stables. Stables on some farms are so faultily constructed 

 that it is almost impossible for the foul air to gain an exit. All 

 stables should have an unlimited supply of pure air, and be so arranged 

 that strong draughts can not blow directly on the animals. Hot 

 stables are almost always illy ventilated, and the hot stable is a cause 

 of disease on account of the extreme change of temperature a horse 

 is liable to when taken out, and extreme changes of temperature are 

 to be avoided as certain causes of disease. A horse taken from i)as- 

 ture and kept in a hot stable is almost sure to contract a cold; the 

 stable should be thrown open and the temperature gradually increased 

 in such cases, when practicable, to avoid the sudden change. 



A cold, close stable is invariably damp, and is to be avoided as 

 much as the hot, close, and foul stable. Horses changed from a cold 

 to a Avarm stable are more liable to contract cold than when changed 

 from a warm to a cold stable. Pure air is more essential than warmth, 

 and this fact should be especially remembered when the stable is made 

 close and foul to gain the warmth. It is more economical to keep the 

 horse warm with blankets than to prevent the ingress of pure air in 

 order to make the stable warm. 



Stables should be well drained and kept clean. Some farmers allow 

 dung to accumulate in the stalls until tliere is hardlj' sufficient room 

 for the liorses. This is a pernicious i)ractice, as the decomposing 

 organic matter evolves poisonous gases that are predisposing or excit- 

 ing causes of disease. When a horse is overheated it is not safe to 



