70 DISEASES OF THE PERICARDIUM 



influence upon it. The average frequency for small animals 

 is as follows: 



Dogs ... . ■■ 60-200 



Cats ... . 100-180 



Rabbits . 110-140 



Birds . . . . 120-180 



An abnormal increase in the pulse is found in all elevations 

 of temperature, in severe injuries (fractures of bones, etc.), 

 in mental excitement, valvular defects, severe hemorrhage, 

 and in heart weakness from any cause. 



A decrease in frequency, or slow pulse, occurs in the later 

 stages of some poisonings, diseases of the brain (chronic 

 and subacute hydrocephalus), tumors in the brain, icterus 

 gravis, collapse, etc. 



(b) The rhythm of the pulse should be regular, especially 

 in cats, rabbits and birds; in the dog an irregular pulse is 

 found so frequently in apparently healthy animals, that it 

 should not be looked upon as an abnormal condition; in fact, 

 an irregular pulse in the dog is the rule. An irregular or 

 arhythmic pulse is therefore a physiological condition in some 

 of the small animals. However, in many pathological con- 

 ditions a pronounced irregularity occurs as, during convales- 

 cence from infectious diseases, severe gastro-intestinal dis- 

 turbances, severe weakness, and in some chronic constitu- 

 tional diseases. An irregular pulse is observed often after 

 large doses of digitalis. 



(c) The quality of the pulse. The pulse beat should be 

 of equal volume, and it varies with the different species of 

 animal. In all small animals the pulse is rapid, strong and 

 hard. In the dog an unequal pulse is frequently observed. 

 The pulse is full and distended after exercise, during the early 

 stages of a number of diseases; empty after severe hemor- 

 rhage, intense heart weakness and collapse. The pulse is 

 hard and full in severe pain, peritonitis, and acute brain 

 diseases. 



The venous pulse is often observed in old dogs and is 

 usually indicative of some chronic heart affection, or general 

 heart weakness. 



