DISEASES OF THE HORSE. 15 



round, soft, dough-like swellings occur on the skin and may be 

 scattered freely over the surface of the body when the horse is 

 afflicted with urticaria. Similar eruptions, but distributed less gen- 

 erail}^, about the size of a silver dollar, may occur as a symptom of 

 dourine, or colt distemper. Hard lumps, from which radiate weJt- 

 like swellings of the lymphatics, occur in glanders, and blisterlike 

 eruptions occur around the mouth and pasterns in horsepox. 



THE ORGANS OF CIRCULATION. 



The first item in this portion of the examination consists in taking 

 the pulse. The pulse may be counted and its character may be 

 determined at any point where a large artery occupies a situation 

 close to the skin and above a hard tissue, such as a bone, cartilage, or 

 tendon. The most convenient place for taking the pulse of the horse 

 is at the jaw. The external maxillary artery runs from between the 

 jaws, around the lower border of the jawbone and up on the outside 

 of the jawbone to the face. It is located immediately in front of the 

 heavy muscles of the cheek. Its throb can be felt most distinctly 

 just before it turns around the 16wer border of the jawbone. The 

 balls of the first and second or of the second and third fingers should 

 be pressed lightly on the skin over this arteiy when its pulsations are 

 to be studied. 



The normal pulse of the healthy horse varies in frequency as follows: 



Stallion 28 to 32 beats per minute. 



Gelding 33 to 38 beats per minute. 



Mare 34 to 40 beats per minute. 



Foal 2 to 3 years old 40 to 50 beats per minute. 



Foal 6 to 12 months old 45 to 60 beats per minute. 



Foal 2 to 4 weeks old 70 to 90 beats per minute. 



The pulse is accelerated hy the digestion of rich food, by hot 

 weather, exercise, excitement, and alarm. It is slightly more rapid 

 in the evening than it is in the morning. Well-bred horses have a 

 slightly more rapid pulse than sluggish, cold-blooded horses. The 

 pulse should be regular; that is, the separate beats should follow each 

 other after intervals of equal length, and the beats should be of equal 

 fullness, or volume. 



In disease, the pulse may become slower or more xapid than in 

 health. Slowing of the pulse msij be caused by old age, great exhaus- 

 tion, or excessi^'e cold. It maj'- be due to depression of the central 

 nervous sj'stem, as in dumminess, or be the result of the administra- 

 tion of drugs, such as digitalis or strophantus. A rapid pulse is 

 almost alwa3^s found in fever, and the more severe the infection and 

 the weaker the heart, the more rapid is the pulse. Under these con- 

 ditions, the beats may rise to 80, 90, or even 120 per minute. When 

 the pulse is above 100 per minute the outlook for recoveiy is not 



