•v 



286 AMERICAN FARMER'S HORSE BOOK. 



which flows a transparent mucus, which is pressed out in the 

 act of swallowing, and is designed to lubricate the throat, so 

 that the food may pass without friction through the pharynx 

 into the oesophagus, on its way to the stomach. The tonsils 

 are often sore and swollen; the little openings close, so that 

 . no mucus flows from them ; the mouth and throat become 

 dry and irritable, and then there is coughing. This act is 

 simply an efibrt, often involuntary, to obtain relief from the 

 dry, itchy, and irritable feeling in the throat, and to force the 

 tonsils to disgorge the mucus from its cells; and when a suf- 

 ficient quantity has been forced out by the pressure of the 

 muscles, in coughing, to once more lubricate the throat, the 

 unpleasant sensations subside, there is a temporary respite, 

 and the cough ceases for awhile. 



The horse, however, has no tonsils such as the human 

 species is furnished with, and hence his cough can not pro- 

 ceed from exactly the same cause as that here mentioned ; 

 yet the same eff*ect is produced in his case by dryness of the 

 lining membrane of the trachea and air-passages of the lungs. 

 The secretions of the parotid and other glands furnish a vapor 

 to the warm air, as it is inhaled in the act of respiration, and 

 this vapor is deposited on the smooth, delicate mucous mem- 

 brane which lines the nasal cavities, the mouth, the throat, 

 and air-passages, and serves to keep it moist. Inflammation 

 and fever tend to evaporate this moisture much faster than 

 it is supplied, and the membrane is left dry. Coughing is 

 the method by which Kature seeks to force an increased sup- 

 ply of moisture from the glands, in order that the membrane 

 may receive the vapory deposits necessary to its comfort. 



One very important object obtained by the act of coughing 

 is the disgorgement of the morbid secretions, which are 

 ' thrown out by the glands of the mouth and throat, and some- 

 times by the lungs. Instead of being a thin, transparent 

 fluid, these are changed into a thick, coagulated mucus, 

 sometimes even tough and stringy in character. Of this 

 large quantities are removed in the acts of coughing and ex- 

 pectoration, and the relief thus obtained is very great. Much 



