Diseases of the Heart and Organs of Circulation. 305 



fleeted on the investing sac, resembles that caused by passing the 

 palm of the one hand over the other which lies on the ear. It is 

 distinguished from the friction sound of pleurisy by its coinciding 

 with the movements of the heart and not with those of respiration. 

 It is usually heard alike during the sounds of the heart and dur- 

 ing the period of .silence or in other words during the movements 

 of contraction and dilatation in that organ. 



General Symptoms of Heart disease. In the acute inflam- 

 matory affections there are the signs of general constitutional dis- 

 turbance attending similar affections in other organs. The decis- 

 ion as to the true nature of the disease must be arrived at from the 

 special character of the pulse, heart sounds, etc. as already noticed. 



In the chronic forms of the disease however a particular class of 

 symptoms usually point towards the organ affected. In cattle, 

 sheep and pigs raised only for slaughter, and as far as possible 

 protected against active exertion, serious heart diseases may exist 

 for a length of time without making themselves manifest by any 

 prominent symptoms. Thus in cows, pins and other sharp pointed 

 bodies swallowed with the food frequently make their way to the 

 heart and lodge for a length of time in its vicinity without mate- 

 rial derangement and when at last the animal dies a .sudden death 

 they are found transfixing the walls of that organ. In the horse 

 or other animal subjected to exertion the symptoms are usually 

 very patent. 



When the heart is enlarged the pulse strong and the circula- 

 tion full and free, apoplexies or hemorrhages especially on the 

 brain or other soft organs where the resistance is least, are liable 

 to occur. When on the other hand the circulation is weak from 

 atrophy or fatty degeneration of the heart, or from insufficiency 

 of the valves there is a tendency to coldness of the extremities, 

 and to passive congestions with their consequences : — serous effu- 

 sions, dropsies, and difficult breathing. The imperfect supply of 

 blood to the muscles of the extremities sometimes brings about an 

 unsteadiness of gait in the hind limbs when the animal is trotted 

 for a short distance and sometimes cramps supervene. 



Continued coldness of the limbs, and a filling or thickening first 

 of the hind limbs then of the fore and lastly of the chest and belly 

 and of the skin beneath their dependent parts are useful indica- 

 tions. 



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