DISEASES OF THE HEART 461 



tions involving the fine membrane which lines the cavities of the heart, 

 and these two morbid states are designated by different terms according 

 with the position occupied by the structures. Where infiammation affects 

 the former it is spoken of as pericarditis, or inflammation of the investing 

 membrane; while the term e^idocarditis is used to indicate inflammation of 

 the membrane which lines the cavities of the heart and contributes to the 

 formation of the different valves. Inflammation of the valvular structures 

 is also distinguished by the term valvulitis. Inflammation, acute or 

 chronic, of the muscular structure of the heart is described as myocarditis, 

 which is commonly associated with inflammation of the membrane investing 

 or linino- the heart. 



PERICARDITIS— INFLAMMATION OF THE HEART SAC 



Inflammation of the pericardium may occur under a variety of circum- 

 stances, sometimes in connection with rheumatism, strangles, and influenza, 

 or any low form of fever or specific blood disease. It may also arise from 

 injury, such as a wound inflicted from without, or from the passage of some 

 foreign body from the digestive organs, through the diaphragm into the 

 pericardial sac. This cause is comparatively frequent in cattle, but is 

 extremely rare in the horse. One case is recorded in which a sewing- 

 needle had passed through the oesophagus into the pericardium, and subse- 

 quently reached the right auricle of the heart. 



As in other cases of disease connected with the central circulatory organ, 

 pericarditis, especially the chronic form, may exist for a considerable period 

 without any symptoms being present which would lead to the suspicion of 

 its existence. This is particularly the case in reference to what is called 

 traumatic pericarditis in cattle. These animals, when at pasture, frequently 

 swallow various extraneous substances which come in their way, and among 

 foreign cattle kept by small owners, and fed very much about the dwelling- 

 houses, it used to be extremely common to find in the rumen of the animals, 

 which were sent to this country for slaughter, various domestic articles, 

 such as brushes, tin or other toys, hair-pins, shawl-pins, skewers, knitting- 

 needles, and even portions of wearing apparel. 



In post-mortem examination it frequently happens that a needle, or 

 piece of wire, or a skewer, is detected in the heart sac, and its path can 

 be traced through the second stomach (reticulum), which lies close to the 

 diaphragm, and from that organ into the pericardial sac, and sometimes 

 into the muscular structure of the heart. In other cases, where the body 

 which has inflicted the injury has been lost in the course of the examina- 

 tion, the path which it has taken can be distinctly followed from the 



