THE EXAMINATION OF A SICK HORSE. 15 



has just been exercised, the impact is stronger than when the horse is 

 at rest. If the horse is weak, the impact is reduced in force. 



The examination of the heart with the ear is an important matter in 

 this connection. Certain sounds are produced by each contraction of 

 the normal heart. It is customary to divide these into two, and to 

 call them the first and second sounds. These two sounds are heard 

 during each pulsation, and any deviation of the normal indicates some 

 alteration in the structure or the functions of the heart. In making 

 this examination, one may apply the left ear over the heavy muscles 

 of the shoulder back of the shoulder joint, and just above the point of 

 the elbow, or, if the sounds are not heard distinctly, the left fore leg 

 may be drawn forward by an assistant and the right ear placed 

 against the lower portion of the chest wall that is exposed in this 

 manner. 



The first sound of the heart occurs while the heart muscle is con- 

 tracting and while the blood is being forced from the heart and the 

 valves are rendered taut to prevent the return of the blood from the 

 lower to the upper chambers. The second sound follows quickly after 

 the first and occurs during rebound of blood in the arteries, caus- 

 ing pressure in the aorta and tensions of the valves guarding its open- 

 ing into the left ventricle. The first sound is of a high pitch and is 

 longer and more distinct than the second. Under the influence of 

 disease these sounds may be altered in various ways. It is not profit- 

 able, in a work such as this, to describe the details of these alterations. 

 Those who are interested will find this subject fully discussed in the 

 veterinary textbooks. 



TEMPERATURE. 



The temperature of the horse is determined roughly by placing 

 the fingers in the mouth or between the thighs or by allowing the 

 horse to exhale against the cheek or back of the hand. In accurate 

 examination, however, these means of determining temperature are 

 not relied upon, but recourse is had to the use of the thermometer. 

 The thermometer used for taking the temperature of a horse is a 

 .self-registering clinical thermometer, similar to that used by phy- 

 sicians, but larger, being from 5 to 6 inches long. The temperature 

 of the animal is measured in the rectum. 



The normal temperature of the horse varies somewhat under dif- 

 ferent conditions. It is higher in the young animal than in the old, 

 and is higher in hot weather than in cold. The weather and exer- 

 cise decidedly influence the temperature physiologically. The nor- 

 mal temperature varies from 99.5° to 101° F. If the temperature 

 rises to 102.5° the horse is said to have a low fever; if the tempera- 

 ture reaches 104° the fever is moderate; if it reaches 106° it is high, 



