ACUTE ENDOCARDITIS IN THE HORSE. II7 



by M. Trasbot in the Archives VHcrinaircs for the years 1878 and 



Although the causation and pathology of acute endocarditis are 

 complex, you may regard it as certain that the affection is always 

 secondary, and produced by toxic infection ; and furthermore, that 

 it is much more frequently due to pulmonary inflammation than 

 has hitherto been admitted. The endocardium is known to be par- 

 ticularly sensitive to the action of infectious processes, and to be easil}' 

 injured by microbes and their toxins. In pneumonia, and especially 

 in the contagious form, the lung is the seat of active microbic growth. 

 Infectious agents passing into the still pervious pulmonary vessels 

 have but a short distance to traverse before reaching the heart, and we 

 well know that they are capable of producing disturbance in viscera 

 much more distant from the lung. Suspended in the blood they neces- 

 sarily pass through the left heart ; they may adhere to the endocardium, 

 appearing in such case specially to affect the irregularities, prominences, 

 and folds in the serous coat, especially in that covering the valves, 

 which, as we know, are the most common seat of the lesions of acute 

 endocarditis. This localisation of the process on the valves is evidently 

 due to incessantly repeated " quasi injuries," resulting from the 

 heart's own action, the free edges of the auriculo-ventricular valves 

 during systole, and of the semilunar valves during diastole being 

 violently hurled backwards and forwards. This explains their vulner- 

 ability at these points, and the readiness with which the}- become 

 inoculated when bathed in infected blood. 



In addition to surgical infections, strangles, influenza, pneumo- 

 enteritis resulting from bad fodder, glanders, and, in fact, all morbid 

 conditions due to the presence of microbes in the lungs, may be 

 accompanied by endocarditis. The blood may become infected 

 through trifling lesions of the skin or mucous membrane — in fact 

 the points of entry for pathogenic organisms are innumerable, and 

 though sometimes easy to identify, are oftener undiscoverable. 



At the autopsy of an old horse, M. Blanc found ulcerative endo- 

 carditis consecutive to inflammation of the biliary ducts. A less 

 careful observer would have recorded this as primary in origin, or due 

 to chill. 



It should be remarked that the lesions are usually localised in the 

 left heart, even wlien the infections agents enter the veins of the systemic 

 circulation, and therefore first reach the right heart. This commoner 

 affection of the left heart has been explained in various ways. Some 

 consider it due to the more active function of this part of the organ, 



