PALPITATIONS IN THE HORSE. 463 



or upon the pericardium. Wounds of the heart, which are quite 

 common in the ox, rarer in the horse, commotions and contusions 

 of this organ (Trékit), may also occasion it. 



Pathological anatomy. The alterations of the myocardium 

 are very varied ; they depend upon the nature of the trouble, 

 whether there is a parenchymatous, interstitial, indurated, or sup- 

 purative myocarditis; but they are always more or less circum- 

 scribed, never diffuse. 



1. In acute parenchymatous myocarditis, which is extremely rare, 

 the inflammation does not exclusively involve the muscular fibres ; 

 it is accompanied by an interstitial elementary infiltration. Johne 

 has described, in the ox, two cases of this form of myocarditis ; 

 the macroscopic alterations consist of softening centres, which are 

 reddish-gray, yellowish gray, or yellowish-white; on the surface 

 of these lesions the fibrillary aspect of the muscle had disappeared; 

 on section the tissue seemed homogeneous. With the microscope 

 were observed the disappearance of the transverse striae, granulous 

 turbidity of the muscular fibres, and a cellular infiltration of the 

 interstitial connective tissue, which was so abundant that the mus- 

 cular fibres were separated from one another by layers of embryonic 

 cells which were three to five times thicker than the fibres them- 

 selves. We have observed a case entirely similar in a horse which 

 had died from contagious pneumonia. At the autopsy of a mare 

 Sanson also found parenchymatous alterations, ecchymoses, and a 

 yellowish serous infiltration of the myocardium. 



2. Indurated chronic myocarditis is marked by the presence, in 

 the myocardium, of milky sjwts (cardio-sclerosis), true cicatricial 

 centres, with which the muscle is filled and which are especially 

 found toward the apex and in the wall of the left heart. These 

 indurations are always depressed upon the surface of the heart ; 

 often we find quite deep excavations upon their area (cardiac 

 aneurism). In some cases we find the muscular fibrils undergoing 

 a process of granulo-fatty degeneration and surrounded by an 

 abundant fibrous connective-tissue neoformation (Friedberger). The 

 process has as an initial lesion a cellular infiltration of the inter- 

 stitial connective tissue; the induration, the fibrinous transforma- 

 tion, characterize its previous stages; this state leads usually to 

 secondary hypertrophy of the heart.^ 



1 Delarnotte has mentioned two cases of cardiac sclerosis in the horse. In one the 

 microscopic examination of the myocardium has been made by Montane. The mus- 



