THE LUNGS- X 1 



and in cases of fever or. extended inflammatory action, it is decidedly 

 the best place for bleeding. In local inflammation blood may be taker 

 from any of the superficial veins. In supposed affections of the shoulder^ 

 or of the fore-leg or foot, the p/a/e vein, w hich comes from the inside of 

 the arm, and runs upwards directly in I'ront of it towards the jugular 

 may be opened. In affections of the hinder extremity, blood is some 

 times abstracted from the saphoena, or thigh-vein, which runs across th«> 

 inside of the thigh. In foot cases it may be taken from the coronet, or 

 much more safely, from the toe ; not by cutting out, as the farrier does, a 

 piece of the sole at the top of the frog, which sometimes causes a wound 

 difficult to heal, and followed by festering, and even by canker ; but cutting 

 down with a fine drawing-knife, called a searcher, at the union between 

 tlie crust and the sole at the very toe until the blood flows, and, if neces- 

 sary, encouraging its discharge by. dipping the foot in warm water. The 

 mesh-work of both arteries and veins will be here divided, and blood ia 

 generally obtained in any quantity that may be needed. The bleeding 

 may be stopped with the greatest ease, by placing a bit of tow in the little 

 groove that has been cut, and tacking the shoe over it. 



THE LUNGS. 



The chest, likewise, contains the lungs, most important from the oflice 

 which they discharge, and the diseases to which they are liable. There are 

 two lungs, the right and the left, separated from each other by the medias- 

 tinum. The right lung is larger than the left, because the heart, inclining 

 to the left, leaves less room on that side of the chest. Each of the lungs is 

 likewise partially divided into lobes ; the right lung contains three, and the 

 left two. When the windpipe enters the chest, it divides into two parts, one 

 going to each lung ; and when these reach the substance of the lungs, they 

 separate into innumerable branches, each terminating in a little bag or 

 cell. These branches, with the cells attached to them, bear no slight re- 

 semblance to bunches of minute grapes. Around these cells spread count- 

 less blood-vessels, being the extreme ramifications of those which conveyed 

 the blood from the right side of the heart to the lungs, and the commence- 

 ment of those which carry it back from the lungs to the left side of the 

 heart ; and the cells and the blood-vessels are connected together by an 

 intervening substance of a fibrous and cellular texture. 



The office of the lungs may be very shortly stated. The blood passing 

 through the capillaries of the body, and contributing to the nourishment of 

 the frame, and furnishing all the secretions, becomes, as we have described, 

 changed. It is no longer able to support life: it is possessed of a poi- 

 sonoiis principle, and that principle is a superabundance of a substance 

 called carbon, which must be got rid of before the blood can again be 

 usefully employed. There is an ingredient in the atmospheric air, called 

 oxygen, which has a strong attraction for this carbon, and which will unite 

 with it wherever it finds it. The chest enlarges by the action of the dia- 

 phragm, and the intercostal and other muscles, as we have narrated ; and 

 the lungs expanding with the chest, in order to fill up the vacuum which 

 would otherwise exist between them and the sides of the chest, these cells 

 enlarge, and a kind of vacuum is formed in each of them, and the air 

 rushes down and fills them ; and being divided from the venous and 

 poisoned blood by these membranes alone, it is enabled to act upon the 

 olood, and attracts from it this carbon, and thus purifies it, and renders it 

 arterial blood, and fit for the purposes of life. This being accomplished, 

 the chest contracts, and the lungs are pressed into smaller compa.ss, and 



