EXAMINATION OF A SK'K HORSE. 17 



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 i)ortion 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 j^revent 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 sticli 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 liack 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-register- 

 ing 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 young animal than in the old, and 

 is higher in hot weather than in cold. The Aveather and exercise de- 

 cidedly influence the temj^erature physiologically. The normal tem- 

 perature varies from 09.5° to 101° F. If the temperature rises to 

 102.5° the horse is said to have a low fever; if the teuij^erature reaches 

 104° the fever is moderate; if it reaches 100° it is high, and above this 

 l^oint 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 100°. A tem- 

 jierature 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- 

 ary to begin by noting the fi-(Hpiency of the respiratory movements. 

 This point can be determined by observing the motions of the nostrils 

 or of the flanks: on a cohl day one can see the condensation of the 

 moisture of the warm air as it comes from the lungs. The nornuil 

 H. Doc. 795, 51)-2 2 



