18 BUKEAU OF A^^IXAL IliDUSTKY. 



moisture of the warm air as it comes from the luno-s. The normal 

 rate ot respiration for a health}' horse at rest is from S to 16 per min- 

 ute. The rate is faster in 3'oung animals than in old, and is increased 

 by work, hot weather, overfilling of the stomach, pregnane}", lyinj*' 

 upon the side, etc. Acceleration of the respiratory rate where no 

 physiological cause operates is due to a variety of conditions. Among 

 these is fever; restricted area of active lung tissue, from filling of poi 

 tions of the lungs with inflammatory exudate, as in pneumonia; com 

 pression of the kings or loss of elasticity; pain in the muscles con- 

 trolling the respiratory movements; excess of carbon-dioxide in the 

 blood; and constriction of the air passages leading to the lungs. 



Difficult or labored respiration is known as dyspnea. It occurs 

 when it is difficult, for any reason, for the animal to obtain the 

 amount of oxygen that it requires. This may be due to filling of the 

 lungs, as in pneumonia; to painful movements of the chest, as in rheu- 

 matism or pleurisy; to tumors of the nose and paralysis of the throat, 

 swellings of the throat, foreign bodies, or weakness of the respiratory 

 passages, fluid in the chest cavity, adhesions between the lungs and 

 chest walls, loss of elasticity of the lungs, etc. Where the difficulty- 

 is great the accessory muscles of respiration are brought into play. 

 In great dyspnea the horse stands with his front feet apart, with his 

 neck straight out, and his head extended upon his neck. The nostrils 

 are widely dilated, the face has an anxious expression, the eyeballs pro- 

 trude, the up-and-down motion of the larynx is aggravated, the ampli- 

 tude of the movement of the chest walls increas'ed, and the flanks 

 heave. 



The expired air is of about the tcm.perature of the body. It contains 

 considerable moisture, and it should come with ec^ual force from each 

 nostril and should not have an unpleasant odor. If the stream of air 

 from one nostril is stronger than from the other, there is an indication 

 of an obstruction in a nasal chamber. If the air possesses a bad odor, 

 it is usually an indication of putrefaction of a tissue or secretion in 

 some part of the respiratory tract. A bad odor is found where there 

 is necrosis of the bone in the nasal passages or in chronic catarrh. 

 An ulcerating tumor of the nose or throat may cause the breath to 

 have an offensive odor. The most offensive breath occurs av here there 

 is necrosis, or gangrene, of the lungs. 



In some diseases there is a discharge from the nose. In order to 

 determine the significance of the discharge it should be examined 

 closely. One should ascertain whether it comes from one or both 

 nostrils. If but from one nostril, it probably originates in the head. 

 The color should be noted. A thin, watery discharge may be composed 

 of serum, and it occurs in the earlier stages of coryza or nasal catarrh. 

 An opalescent, slightly tinted discharge is composed of mucus and 

 indicates a little more severe irritation. If the discharge is sticky and 



