156 DISEASES OF THE CIRCULATORY APPARATUS 



Character of the Heart Pulsations. 



The pulsations of the heart can be distinguished by putting the hand 

 on the inferior portion of the chest near the sternum, about the fifth rib 

 (on the right side the pulsation is situated a little more anteriorly) . The 

 pulsation makes a distinct vibration of all the adjacent parts, and in 

 emaciated animals there can be noticed with each pulsation a distinct 

 swelling or motion of the lower portions of the ribs; this vibration may 

 be greatly lessened by the presence of layers of fat on the sides of the 

 "chest. After great exertion or excitement the strength of the pulsation 

 against the chest- w\all is greatly increased. 



The pulsations of the heart are increased by disease in the following 

 conditions: After considerable loss of blood, in any case of fever, in pal- 

 pitation of the heart, in some forms of heart disease, in hypertrophy of 

 the heart, or by the influence of some poisons, such as digitalis or aconite. 

 It is almost imperceptible in degeneration of the muscle of the heart, 

 in the later stages of acute diseases, in cases of poisoning, in fatty de- 

 generation of the heart, and when the heart has become compressed by 

 the effects of hydrothorax, pneumopericarditis, or emphysema of the 

 lungs. It is distinguished only on the healthy side in lateral pleuritis. 



Character of the Heart Sounds and Bruits. 



In order to distinguish the heart sounds we must put the ear close 

 to the side directly over the heart where the beats are loudest; it is better 

 to cover the place with a handkerchief or cloth, or we may use a stetho- 

 scope. We should hear two sounds in each heart beat — a systolic, 

 which corresponds to the ventricular contraction, and a diastolic, which 

 corresponds with the beginning of the diastole. Both these sounds follow 

 each other with short intervals between. The pause between the first and 

 second sound is short, but between the second and the next first the sound 

 is much greater. The first sound is a mixed muscular and valvular 

 sound of the mitrals and tricuspids, and the second is a semilunar val- 

 vular sound. 



Unfortunately these sounds are indistinct and mcomplete in the 

 dog, even in perfect health. In very fat dogs we may not hear any heart 

 sound, or we may only hear the first one. In well-fed dogs it is not rare 

 to hear the first sound, which is a great deal louder than the second, 

 only on the left side. In thin animals we can hear the sound distinctly 

 on both sides. AVith the respiratory bruit we lose to a certain extent the 

 full strength of the sounds, and often only the first sound is heard. After 

 great activity the heart's action is increased so much, and the sounds 



