CALCIFICATION OF THE HEART. 581 



general tonic treatment, with, in cases of special cardiac irrita- 

 bility, the use of such agents as seem to possess a special 

 power of influencing the heart's action, are the indications we 

 require to follow, and from which the greatest benefit may be 

 expected. The different preparations of iron, combined with 

 the common vegetable tonics and diuretics, or with such agents 

 as nux vomica or digitalis, are those chiefly employed. 



The prognosis in all these cases is certain as to the ultimate 

 results, but may not be determined as to time ; the animal 

 may continue to work for a longer or shorter period, but, as 

 the disease progresses, usually succumbs suddenly, and oftener 

 from the rapid progress of some of the secondary affections 

 than from the original disease. 



VII. Calcification of the Heart. 



Of this peculiar and rare condition of the muscular sub- 

 stance of the heart we know little ; cases, however, are recorded 

 of its existence. One is mentioned by Mr. Percivall as having 

 been met with in the practice of the late Mr. Henderson, 

 London. The only history attached to this is that the animal, 

 m an emaciated condition, dropped dead while at work in a 

 dust-cart. Of another mentioned in the Receuil de Medecine 

 Veterinaire for 1840, it is recorded that, although a young 

 animal, he was unable to work from recurring and persisting 

 attacks of exhaustion and dyspnoea, and that death appeared 

 at last to result from an attack of pneumonia. In both these 

 instances it was the right auricle which had undergone the 

 calcifying change. 



CHAPTER XXXI. 



DISEASES OF THE PERITONEUM. 



I. Peritonitis. 



Definition. — Infiammation of the serous membrane lining the 

 cavity and covering the viscera contained in the abdomen. 



Pathology. — Although of all our patients it is probable that 

 the horse can tolerate least of all interference in any way with 



