DISEASES OF TDE HEART AND ITS MEMBEANES. boo 



of heart disease are absent; if persistent, they indicate, separately 

 or conjointly, some organic lesion of the heart or its membranes. 

 Repeated examinations of the patients are necessary before 

 forming a conclusion. 



(b.) Organic Diseases. — Carditis, or inflammation of the sub- 

 stance of the heart, is always circumscribed ; a general or diffused 

 inflammation, which would be immediately fatal in consequence 

 of destruction of function, is fortunately never witnessed. Partial 

 or circumscribed carditis, unless it be due to injuries, and asso- 

 ciated with exocardial effusion and exudation, presents no 

 symptoms during life, and is only discoverable jwst viortem by 

 the presence of a small abscess or circumscribed deposits of 

 lymph ; but although the cardiac walls are not subject to inflam- 

 mation, they undergo various alterations inimical to the well- 

 being of the animal, and may be described as follows. 



1. Hypertrophy. — This may be of three kinds : — 



(1.) Simple hypcrtro]}hy, where the walls are merely thickened 

 without alteration of the cavity. 



(2.) Eccentric hypertrophy, where the walls are thickened 

 and the cavities enlarged. 



(3.) Concentric hypertrophy, where the walls are thickened 

 and the cavities diminished. 



These conditions are manifested by a more or less persistent 

 palpitation or increased cardiac force, the cardiac sounds being 

 often heard upon both sides of the chest. They are due to some 

 obstruction to the circulation consequent upon chronic pul- 

 monary disease, constriction of some of the large vessels, and 

 are best combated by a moderate diet, freedom from excitement, 

 and, if depending upon broken wind or any impediment to the 

 pulmonary circulation, by small doses of arsenic. 



The most common organic change which occurs in the hearts 

 of horses and dogs is that due to atrophy and fatty degeneration. 

 This change is generally met with in aged subjects, and in those 

 wdiich have been pampered and irregularly exercised. It is also 

 a result of pericarditis, and as a sequel to epizootic diseases in 

 which the pericardium has been involved. It is also induced 

 by blood aflections, as purpura, azoturia, and scarlatina. 



During life the progress of atrophy and degeneration is mani- 

 fested by a more or less slowly increasing debility of the 

 circulation exemplified by diminished cardiac impulse, irregu- 



