352 DISEASES OF BEEATHINa. 



them becomes inflamed, the lungs will in all probability, partici- 

 pate in the derangement. Hence, we more frequently find broncho- 

 pneumonia, or pleuro-pneumonia, than pneumonia, pleurisy, or 

 bronchitis in a pure form. I shall briefly describe the respective 

 sjTuptoms of the three last-named diseases, so that the reader may 

 draw his own inferences in complicated cases, which present far too 

 great a variety to admit of detailed description ; and shall, finally, 

 give the general treatment which is applicable to all of them, 

 with such special directions as the symptoms may indicate. 



Generally speaking, these diseases occur in four ways : (1.) By 

 exposure to cold, especially in combination with a damp and 

 draughty condition of the surrounding air, and when the system 

 is over-heated, debilitated, or exhausted from excessive exertion. 

 (2.) By some mechanical irritant, as may happen when a drench of 

 turpentine and oil " goes the wrong way '^ ; or when the sharp end 

 of a broken rib pierces the lung. (3.) As secondary diseases; for 

 instance, when the lungs become invaded with the abscesses of 

 glanders. Under this heading we may include embolic pneumonia, 

 as in inflammation of veins (p. 117). This complication sometimes 

 follows strangles, and other inflammatory conditions which are 

 accompanied by the formation of pus. (4.) As infective diseases; 

 in which case, there is strong reason for believing that they are 

 diseases which involve the entire system, and have a local mani- 

 festation in the organs of breathing. The practical considerations 

 which bear out this view are as follows : (a) These diseases often 

 assume an epizootic type. (6) They run a regular course of about 

 a week or ten days, (c) The treatment which best succeeds, is 

 one based on the theory that the disease isi caused by the presence 

 in the system, of some virus, to remove which we should conse- 

 quently direct our efforts, while at the same time we should support 

 the animal's vital powers. 



The word " epizootic " is applied to animals, in the same manner 

 as " epidemic " is to men. 



In these diseases, as in all other inflammations, there is an 

 escape of watery fluid (plasma, p. 12) from the vessels of the 

 inflamed part, which plasma at first becomes solid, and after- 

 wards breaks up, and is more or less removed. 



As an uninstructed observer of these chest disorders will often 

 be unable to detect the disease in its first stage — the horse, at the 

 outset, usually appearing to him to be simply dull and out of 

 sorts — the attack will in many cases have run a part of its course 

 before its existence is suspected. 



Horse owners should remember that of all stables liable to 

 induce chest diseases, ill-ventilated, damp and draughty ones are 

 the worst. " 



