THE HEART. 121 



Beneath the left lung the heart is situated and partially inclosed in 

 another membranous bag termed the pericardium, which closely 

 invests, supports, and protects it. The heart has two sides, the one 

 devoted to the circulation of the blood through the lungs, and the 

 other to its circulation through the frame generally. Each side is 

 divided into two compartments, the one above, the other below, 

 which are termed the auricles and ventricles. The right auricle as 

 well as the ventricle is larger than the left, and its parietes are thinner. 

 The longitudinal tendinous cords of the ventricle are more firm and 

 distinct in the pig than in the ox or sheep, and the fleshy prominences 

 shorter. The tendinous cords of the left ventricle are few in num- 

 ber, large, and ill defined. The aorta of the pig separates almost 

 immediately after its commencement into two trunks, the smaller of 

 which leads forwards and gives forth those arteries which in other 

 animals arise from the cross of this artery ; and the other, which is 

 longer in diameter, inclines backwards : these are usually termed the 

 anterior and posterior aorta. 



The beating of the heart may be felt on the left side, whence also 

 the pulse may be taken, or from the femoral artery which crosses 

 the inside of the thigh in an oblique direction. In swirie in a state 

 of health the pulsations are from seventy to eighty in a minute. 



DISEASED VALVES OF THE HEART. 



This appears to be a more common malady than is generally 

 suspected, for in repeated cases of sudden death, where a post-mor- 

 tem examination has been made, there have been found fleshy ex- 

 crescences or tumors on the tricuspid valves. We believe Mr. 

 Cartwright, whose name we have already mentioned, was one of the 

 first persons who drew attention to this disease. The only marked 

 precursory symptoms appear to be inappetency and very shortly 

 before death difficulty of breathing and evident distress. In one 

 pig that died thus suddenly, Mr. Cartwright found several uneven 

 watery excrescences, some as large as marbles, growing from the 

 edge of the auricula-ventricular valves of the left side ; also several 

 small papillary growths, all of which served three parts to close up 

 the ventricular opening. 



In another case he found a loose, jagged, watery excrescence grow- 

 ing from the whole surface of the tricuspid valves, closing up, in a 

 great measure, the ventricular opening, and projecting at least half 

 an inch into the left auricle. In a third, the valves of the left auri- 

 cle were thickened, schirrous, and presented a ragged uneven sur- 

 face. The orifice of the ventricle was almost closed up by this dis- 

 eased substance, and a portion had forced its way into the aorta. 

 This disease was always found in the left side of the heart, and ill 

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