A MANUAL ON THE HOG. 75 



towards the abdomen. The anterior convexity abuts 

 upon the lungs, the posterior concavity is occupied* by a 

 portion of the abdominal viscera. The diaphragm of the 

 pig resembles that of the ox, or sheep. 



" The chest is divided into two cavities by a membrane, 

 termed the Diediastinum, which evidently consists of a du- 

 plicate of the pluera, or lining membrane of the thorax. 



" The pleura is a serous membrane, possessed of little or 

 no sensibility, and acted upon by but few nerves. It is 

 smooth and polished ; covers the bony wall of the thorax 

 from the spine to the sternum, (breast-bone), and from the 

 first rib to the diaphragm, and dilating and forming a kind 

 of bag which spreads over and contains the whole of the 

 lung. 



" The lungs (lights) form two distinct bodies, the right be- 

 ing somewhat larger than the left one ; they are separated 

 from each other by that folding over of the pleura, 

 termed the mediastinum, and hence may be said to be in- 

 closed in separate hogs, or to have distinct pleuras. Each 

 lung is sub-divided. The right one consists of three un- 

 equal lobes, the smallest of which is again sub-divided into 

 numerous lobules, differing in number in different swine. 

 The left lung consists of two lobes, and the scissure between 

 these is not very deep. 



" Beneath the left lung the heart is situated, and partially 

 inclosed in another membranous bag, termed the pericar- 

 dium, 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 circula- 

 tion through the frame generally. Each side is divided 

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

 which are termed auricles and- ventricles. The right auricle, 

 as well as the ventricle, is larger than the left, and its pari- 

 etcs (wills) are thinner. 



" The longitudinal tendinous cords of the ventrical are 

 more firm and distinct in the pig than in the ox or sheep, 

 and the fleshy prominences shorter. 



