130 CLINICAL VETERINARY MEDICINE AND SURGERY. 



the short pause, and finally the murmur which covered the second 

 sound, and was prolonged throughout the long pause. 



The pulse was very strong, but was not, however, visible at the 

 superficial arteries. By placing a stethoscope over the carotid towards 

 the lower part of the neck a diastolic murmur could be heard. On 

 auscultating the aorta no abnormal sound was detected. 



In horses suffering from aortic insufiiciency the pulse is almost 

 always strong. You will sometimes find it of normal volume, but 

 rarely feeble. Only a moment's reflection on the changes produced in 

 the heart by aortic insufficiency is required to show that the pulse 

 cannot be feeble so long as the heart muscle continues its function 

 actively. 



Aortic insufficiency produces a number of other symptoms, though 

 they are not special to it. Like all diseases of the heart, it is accom- 

 panied sooner or later by functional troubles, the most important of 

 •which are rapid loss of breath when at work, dyspnoea, pain (causing 

 the animal to wear an anxious look), and a tendency to vertigo. When 

 animals are kept sufficiently long, disturbance of the pulmonary circu- 

 lation may be noted ; passive congestion of the lung in consequence 

 of mitral insufficiency, which again is due to dilatation of the left 

 ventricle, and mechanical enlargement of the auriculo-ventricular 

 orifice ; later still, passive congestion of other viscera, resulting from 

 degeneration of the heart muscle and exhaustion of the heart. But in 

 few horses is the process allowed to reach its last stage, the animals 

 usually being slaughtered as soon as they become incapable of sus- 

 tained work. 



Sudden death following arrest of the heart is rare in horses with 

 aortic insufficiency, though it may occur. I will give you an instance. 

 Five or six years ago a colleague asked me to examine an old cart- 

 horse, which he considered broken-winded. At work the animal's 

 breathing soon became embarrassed, especially when climbing hills and 

 during hot weather, but the cough was not that of emphysema. On 

 auscultating the heart I diagnosed aortic insufficiency, which was 

 clearly indicated by a strong musical diastolic murmur. As other 

 severe constitutional symptoms had existed for a considerable time, 

 my prognosis was grave. The animal worked for a further period of 

 three years. Several times it fell down, but at once rose again, gradu- 

 ally recovered, and after twenty-four hours' rest resumed light work. 

 Finally, one hot day, it fell in the shafts and died in a few moments. 



The diagnosis of aortic insufficiency is easy. The two symptoms 



