576 CHRONIC DISEASES OF THE HEART. 



encountered them in cattle and sheep, have not come under 

 my observation in the horse. Single parasites, wandering indi- 

 viduals of the Strongylus armatus, I have found in the peri- 

 cardial sac of young horses, their presence having evidently 

 been the immediately inducing cause of pericardial inflamma- 

 tion and some other structural changes. 



Occasionally, in decidedly cachectic subjects, the heart may 

 become the seat of malignant or cancerous growths, the 

 appearance of which may usually be regarded as the sequel to 

 a general invasion of the system by cancer ; although it is per- 

 fectly possible that these malignant growths may appear 

 primarily in the cardiac structures previous to or apart from 

 their existence elsewhere. 



In some instances dilatation of the cardiac veins beneath 

 the endocardial membrane may become so extensive and 

 assume such a form as to be viewed as vascular cardiac 

 tumours. The most frequently encountered cardiac growths 

 are probably the fibrinous, often situated in the interior of the 

 cavities of the heart. In speaking of these fibrinous growths, 

 or cardiac polypi, we must not forget that there is a danger of 

 confounding these with the existence of fibrinous coagula, or 

 thrombi, often found in the cardiac cavities, and which, 

 although they may be of ante-mortem formation, are yet dis- 

 tinct from the true polypi which have obtained a true and 

 intimate connection with the muscular walls. When present, 

 the fibrinous growths seem to arise from the muscular tissue 

 beneath the endocardial membrane. They may reach a con- 

 siderable size without their existence being suspected during 

 life, and seem, from their anatomical structure, to steadily 

 increase in growth through attraction and incorporation of 

 fibrinogenous and lymphoid materials. AVhen examined care- 

 fully, the interior and portions closely connected with the 

 peduncle are evidently more perfectly organized and fibrillated 

 than the outer and more superficial parts. These growths, 

 although found in the hearts of horses, seem, from the re- 

 corded cases, to be more common in cattle ; I have met with 

 them in both animals, and their existence has struck me as 

 most likely to have arisen in consequence of limited endocar- 

 ditis, and that they steadil}^ increase in bulk from the depo- 

 sition over the original seat of some inflammatory exudate of 



