DISEASES OF THE HORSE. 17 



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 

 ma}^ 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, causing 

 pressure in the aorta and tensions of the valves guarding its opening 

 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 profital^lcy 

 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 text-books. 



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 examina- 

 tion, however, these means of determining temperature are not relied 

 upon, but recourse is had to the use of the thermometer. The ther- 

 mometer used for taking the temperature of a horse is a self -registering 

 clinical thermometer, similar to that used by physicians, 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 differ- 

 ent conditions. It is higher in the J^oung animal than in the old, and 

 is higher in hot weather than in cold. The weather and exercise 

 decidedly influence the temperature physiologically. The normal 

 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 temperature reaches 

 101° the fever is moderate; if it reaches 106° it is high, and above this 

 point it is regarded as very high. In some diseases, such as tetanus 

 or sunstroke, the temperature goes as high as 108° or 110°. In the 

 ordinary infectious diseases it does not often exceed 106°. A tempera- 

 ture of 107.5° and above is very dangerous and must be reduced 

 promptly if the horse is to be saved. 



THE ORGANS OF RESPIRATION. 



In examining this system of organs and their functions it is custom- 



ar}^ to begin hy noting the frequency of the respiratory movements. 



This point can be determined b}^ observing the motions of the nostrils 



or of the flanks; on a cold day one can see the condensation of the 



11381—03 2 



