74 DISEASES OF CATTLE. 



edge of the flat muscle on the side of the cheek; or, if the cow is lying 

 down, the metacarpal artery on the back part of the fore fetlock is 

 very convenient for the purpose. 



THE EXAMINATION OP THE HEART. 



Corresponding withthe beats of the heart two sounds are emitted, 

 which are of a definite type in healthy animals. The first is pro- 

 duced by the contraction of the heart and the flow of blood out of it; 

 the second is caused by the rebound of blood in the aorta and the 

 closure of the valves that prevent it from flowing backward into the 

 heart, whence it came. The first sound is the longer and louder of 

 the two, though of low pitch. The second sound is sharper and 

 shorter, and is not always easy to hear in cattle. There is a brief 

 interval between them. 



To appreciate these sounds, the ear is placed against the left side of 

 the chest, a little above the point where the elbow rests when the 

 animal is standing in a natural position and about opposite the sixth 

 rib. The heart sounds are both reduced in intensity when the animal 

 is weak or when the heart is forced away from the chest wall by col- 

 lections of fluid or by tubercular or other growths. Nbnrhythmical 

 heart sound is often caused by pericarditis or by disease of the 

 valves. It may also be due to overfilling of the heart upon the right 

 side, as occurs in severe congestion of the lungs and in some febrile 

 diseases. 



In pericarditis scraping, rubbing, or splashing sounds may be heard, 

 entirely apart from the two normal sounds above described. 



The impulse of the heart, as felt by placing the hand against the 

 chest, is of some consequence in arriving at a conclusion in respect to 

 disease of the heart; but it must be remembered that the impulse 

 may be very much increased by diseases other than those of the heart, 

 as, for example, inflammation of various organs, severe pains, etc. 

 The impulse may also be increased (when disease does not exist) by 

 work, exercise, fright, or any cause of excitement, or, in general, by 

 anything that causes acceleration of the pulse. 



The impulse of the heart may be felt and the sounds may be heard 

 fairly well in lean cattle, but in fat ones it is difficult and often 

 impossible to detect either impulse or sound with any degree of satis- 

 faction. 



PALPITATION. 



When the impulse of the heart is excessive— that is, when it beats 

 more or less tumultously— the familiar expression < ' palpitation of the 

 heart " is applied ; and by many it is called ' ' thumps. " The hand or 

 ear placed against the chest easily detects the unnatural beating. In 

 some cases it is so violent that the motion may be seen at a distance. 

 Palpitation is but a symptom, and in many instances not connected 



