Sero-Fibrinous Pericarditis. 443 



pericardial sac. This sound may be at first the finest possible 

 creaking, afterward increasing to a distinct rubbing, is synchron- 

 ous with the beat of the heart, and usually with the first sound. 

 It is distinguished from the friction sound of pleurisy in occurring 

 rhythmically with the sounds of the heart, and not with those of 

 breathing, and from sounds produced in the interior of the heart 

 by its absence when auscultation is made over the carotid or other 

 large artery. This friction sound is lost when serous effusion 

 takes place into the pericardium, but reappears when the liquid 

 is absorbed in the process of recovery. Until effusion takes place 

 the impulse of the heart is strong, often irregular in force, and 

 sometimes accompanied by a purring tremor or, according to 

 lyeblanc, a metallic tinkle. 



When effusion has taken place, the pulse is weaker and softer, 

 irregular or intermittent, the impulse of the heart is weaker, the 

 friction sound is lost, and the area of dullness corresponding to the 

 heart is increased. Percussion shows it to extend higher than 

 three inches above the breast bone in the horse, and more than 

 two or two and a half inches transversely. It is distinguished from 

 the effusion of pleurisy in this, that the dullness is confined to the 

 anterior part of the chest, having the outline of an inverted cone, 

 and does not extend backward along a horizontal line, and, in 

 solipeds, in not showing equally on both sides. In the smaller 

 animals it may be distinguished by not always occupying the de- 

 pendent part of the chest when the animal is placed in different 

 positions. As the effusion increases, the heart's sounds, previ- 

 ously strong, become first muffled, then more and more distant 

 until they may become altogether imperceptible. The difficulty 

 and oppression of the breathing increases, the nose is protruded, 

 the eyes more rigidly fixed, and the face more haggard ; a venous 

 pulse, apparently due to the compression of the heart and large 

 veins by the fluid, is seen in the lower ends of the jugulars, and 

 the animal obstinately stands as indeed the solipeds do all through 

 the disease. At this advanced stage dropsies of the limbs, sheath, 

 and other dependent parts of the body are frequent. 



A painful cough is sometimes, though by no means invariably, 

 present throughout the disease. Emaciation takes place rapidly 

 and in the more acute cases, death ensues in five to eight days. A 

 fatal issue may be delayed until after three weeks, or the affection 

 may merge into a chronic form. 



