THE HOESE AND ITS DISEASES. 87 



filled with air, which has descended through the bron- 

 chial tubes, in the act of inspiration — this delicate 

 membrane permits some of the principal to permeate it. 

 The oxygen of the atmosphere attracts and combines 

 with a portion of the superabundant carbon of the blood, 

 and the expired air is poisoned with carbonic acid gas — 

 some of the constituents of the blood, attract a portion 

 of the oxygen of the air, and obtain their distinguishing 

 character and properties as arterial blood, and being thus 

 revivified, it passes over the membrane of the lobes, 

 unites into small and larger vessels, and at length pours 

 its full stream of arterial blood into the left auricle, 

 thence to ascend into the ventricle, and to be diffused 

 over the frame, 



Nature of the Liver. 



The liver is a large mass, situated on the right side, 

 with a smaller portion on the left hypochondrium, with 

 its convex surface adapted to the convexity of the 

 diaphragm, it is of a dark red color, and about two feet 

 and a half in circumference, being thick towards the 

 middle, but thin at the edges, in the horse divided into 

 several portions, forming two large lobes, and several 

 smaller ones, the same is observed in all animals des- 

 tined for quick motion. The liver is attached to its 

 convex surface to the diaphragm, by productions of the 

 peritonium, and likewise by means of cellular membranes. 

 It is exteriorly covered by the peritonium, and inter- 

 nally within this, there is a considerable layer of cellular 

 tissue that penetrates its substance, and which is 

 furnished with- numerous lymphatic vessels accompany- 

 ing its several portions. 



Uses of the Liver. 



In most animals, the liver is found more evolved at 

 birth than any other organ, the reason of which appears 

 to be, that it receives more blood than other parts, for, 



