CONGESTION OF THE LUNGS. 29 



the bronchial arteries and veins constitute the former, while 

 the latter consists of the pulmonary arteries and veins, and 

 is the system involved in congestion of the lungs. 



Definition. — Congestion of the lungs may be defined as 

 partial or complete arrest of the pulmonary circulation ; a 

 largely increased amount of blood being detained in the parts, 

 causing an enlarged condition and functional derangement 

 of the lungs. Congestion of the lungs is a forerunner of 

 pneumonia and other pulmonary affections, yet it occurs as- 

 an independent disease. 



Causes. — Congestion of the lungs is very common at 

 certain seasons of the year ; in Canada the disease being 

 of most frequent occurrence during the spring ; the ex- 

 planation being that on account of the length and severity 

 of the winter season many horses are kej^t standing in the 

 stable, fed well, and get no exercise ; on the appearance of 

 fine weather they are taken out, put to hard work, and 

 congestion of the lungs is a frequent result. In England 

 the disease is of frequent occurrence amongst hunting 

 horses at the beginning of the hunting season, the horses 

 being jmt to rapid work and severe exertion when not in 

 fit condition. Driving an animal while suffering from an 

 attack of simple catarrh, influenza, etc., quartering in damp, 

 badly ventilated stables, impure air, draughts, etc., are all 

 causes of congestion of the lungs. The condition occurs 

 occasionally as a symptom of cardiac derangement, etc. 

 The disease may, or may not, run a favourable course in a 

 very short period ; a horse may die in twenty-four hours 

 from the time the first symptom was manifested. A very 

 slight congestion is sufficient to cause death, providing a 

 large portion of lung tissue is involved. The disease runs 

 its course to a termination, favourable or otherwise, within 

 a period varying from eight or ten hours to several days. 



Symptoms. — Symptoms vary to a greater or less extent. 



