DISEASES OP THE HEART, BLOOD VESSELS, AND LYMPHATICS. 75 



associated with disease, but may be a symptom of some disease of the 

 heart; in such cases the jugular pulse is continuous. 



The place selected for feeling the pulse in cattle is where the 

 submaxillary artery winds around the lower jawbones, just at the 

 lower 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 OF THE HEART. 



Corresponding to the 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. There is a brief inter\al 

 between them. 



To distinguish 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. Both heart sounds are 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. Nonrhythmical 

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

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

 the right side, as occurs in severe congestion of the lungs and in 

 some febrile diseases. 



In pericarditis, sounds like scraping, rubbing, or splashing 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 reaching 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 be increased also (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 



satisfaction. 



PALPITATION. 



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

 more or less tumultuously — the familiar expression " palpitation of 



