144 DISEASES OF THE CIBCULATOBY APPARATUS. 



Etiology of Deficient Valvular Action of the Heart. 

 The most common causes of valvular defects are endocarditic pro- 

 •cesses, which are developed on the valves and take an acute course, 

 according to the amount of the irritation, and cause a fibrinous, 

 rigid thickening of the valves. Sooner or later we have an im- 

 perfect closing of the valvular opening through cicatricial retrac- 

 tions; also adherences to the lobula of the valves or in their 

 neighborhood. We may also see deposits of lime salts, and a 

 contraction of the opening belonging to the affected valve. lu 

 rare cases there are heart-weakness and imperfect valvular action ; 

 it may be caused by a dilatation of the opening, and, becoming 

 abnormally distended, the valves cannot meet and make a com- 

 plete closure. Atheromatous processes may also produce this con- 

 dition. 



General Symptoms of Deficient Valvular Action of 

 THE Heart. The symptoms which appear at a certain time in 

 all valvular troubles are: Increase of heart- and pulse-action (after 

 slight exertion it is abnormally increased); palpitation of the heart; 

 difficulty in respiration; cyanosis of the visible mucous membranes, 

 especially of the head; venous pulse; dropsical effusions, such as 

 oedema of the legs, abdomen, or testicles; hydrothorax; ascites; 

 albuminuria, with lessening of the amount of urine; complica- 

 tions of the digestive organs of various kinds; and, finally, gen- 

 eral nutritive disturbances, annemia, emaciation, etc. 



Symptoms of Valvular Deficiency in One Opening. 

 Deficiency of the Mitrals. The imperfect closing of two of the 

 valves occurs very frequently in the dog. Besides the alterations 

 -of the valves we find hypertrophy and dilatation of the left aur- 

 icle of the right heart, and in the later stages the right ventricle 

 also. 



The clinical symptoms are: Increase of the pulse and disten- 

 tion of the artery, systolic bruit of the left wall of the chest, in- 

 crease of the second (pulmonic) sound, weak, frequent pulse, 

 shortness of breath, and later dropsy, etc. 



Stenosis of the Left Venous Opening. This is generally accom- 

 panied by mitral insufficiency. It leads also to dilatation and 

 hypertrophy of the left auricle and the right ventricle, and the 

 left ventricle is generally small, narrow, and contains little blood. 



The clinical symptoms are; Slight increase in the pulse, dias- 



