146 CLINICAL VETERINARY MEDICINE AND SURGERY. 



enlargement of the precordial area of dulness ; but these are theoreti- 

 cal points difficult to determine. In common with the action of the 

 heart the pulse becomes feeble, irregular, and intermittent. The 

 functional disturbance produced by myocarditis is seldom pronounced 

 during the first stage of the disease ; and as the condition is almost 

 always secondary, this functional disturbance cannot be differentiated 

 from that due to the infectious disorder of which the heart trouble is 

 only a complication. But the symptoms, especially the dyspnoea, are 

 always aggravated by myocarditis. 



Contrary to what one might imagine, considering the extremely 

 important function of the heart, acute myocarditis terminates in a 

 fairly large number of cases in recovery. This is the rule in the slight 

 forms accompanying infectious conditions. Resolution slowly pro- 

 ceeds, the heart gradually becomes more active, and its contractions 

 more powerful, until at length the sounds resume their normal charac- 

 ter. Clinically recovery is complete, and if anatomically it remains 

 imperfect the disease leaves few traces. In a proportion of cases the 

 inflammation assumes a chronic form. 



Death may occur at all stages ; sometimes suddenly by syncope, 

 sometimes less rapidly by asphyxia. When by asphyxia dyspnoea 

 increases, the face appears extremely anxious, the apex beat of the 

 heart becomes imperceptible, the pulse is lost, cold sweats cover 

 the body ; finally the patient, completely prostrated and unsteady on 

 its legs, falls to the ground and dies in a state of painful collapse. 

 During convalescence death is sometimes produced b}^ granular or 

 hyaline degeneration of the muscular tissue. If in purulent myocar- 

 ditis an abscess opens through the endocardium, death results from 

 purulent infection or cerebral embolism. Cases of this kind are seen 

 in strangles. When myocarditis accompanies an infectious disease 

 which has gravely affected the lung, kidney, or nervous centres, the 

 lesions in these organs play a certain part in producing death. 



The diagnosis of acute myocarditis is difficult. Many infectious 

 diseases entail disturbance of the heart simulating myocarditis, and 

 in addition certain of the local symptoms of myocarditis are also 

 common to pericarditis. Nevertheless, if the practitioner follows the 

 development of the latter disease, other symptoms will be detected 

 which forbid confusion ; and when pericardial effusion is abundant, 

 the precordial dulness and weakness of the heart sounds are much 

 more marked than in myocarditis. 



Speaking generally, the prognosis is grave. Acute m)'ocarditis may 

 lead to sudden death ; in point of fact it kills many animals suffering 



