THE HORSE AND ITS DISEASES. /9 



wrought on the blood in general. Innnmerable proofs 

 may be brought forward to prove that some important 

 alteration is effected in this fluid in its passage through 

 the lungs — every experiment, almost every phenomenon 

 of animal life shews it. The difference between the 

 blood in the arteries and veins, and which blood we 

 all know is derived from the same source, is a most strong 

 and convincing proof. The researches of eminent anato- 

 mists describe the phenomena of life to be effected by 

 the continual wasting and reproduction of the body, by 

 the several actions of life, as breathing, exercise, etc., 

 and therefore this waste of matter is greatly accelerated 

 by exercise, and consequently reproduced as quickly 

 vnth new and strengthening properties. 



Nature and Properties of the Lungs. 



The lungs are the scat of a peculiar cii'culation, they 

 convey through their comparatively little bulk, the blood 

 and other fluids scarcely transformed into blood, or soon 

 separated from it, which traverse the whole of the 

 frame. They consist of countless ramifications of air 

 tubes and blood vessels connected together by intervening 

 cellular substances. 



They form two distinct bodies, the right somewhat 

 larger than the left, and are divided from each other by 

 the duplicature of pleura ; each lung has the same 

 structure, properties, and use, each of them being 

 subdivided, the right lung consisting of three lobes, and 

 the left of two. The intention of these divisions is 

 probably to adapt the substance of the lungs to the form 

 of the cavity in which they are placed, and to enable 

 them more perfectly to occupy and fill the chest. If one 

 of these lobes is cut in two, it is found to consist of 

 innumerable irregularly formed compartments, to which 

 anatomists have given the name lobules, or little lobes. 

 They are distinct from each other, and impervious, on 

 close examination. They can be subdivided almost 



