THE LUNGS. U5.9 



CHAPTER X 



SiLETCH OF THE INTER^^AL OKGANIZATIOIf OF THE nORSE. 



THE LUNGS. 



PLATE IX. Fig. 1., &c. 



The lungs are two spongy bodies formed for the purpose 

 of breathing. Thej are contained in the lateral regions on 

 each side of the chest, a, a, a, separated from each other by 

 the mediastinum and heart, which occupy the middle 

 region. The lungs are two in number, — the right and the 

 left, partitioned from each other by the mediastinum. They 

 are further divided into lobes, that on the right side, which 

 is the larger of the tAvo, consists of three lobes, and the left 

 has only two. These lobes are merely partial divisions, of 

 variable extent, which serves to adapt them more accurately 

 to the cavities of the chest, and at the same time render 

 them fitter for the purposes of expansion and contraction. 

 When the windpipe enters the chest, it is divided into two 

 branches, one extending to each lung ; and when these 

 enter the substance of the lungs, they separate into nume- 

 rous branches, each terminating in a little bag or cell. 

 These bear a considerable resemblance to minute bunches of 

 grapes. Around these cells are spread innumerable blood- 

 vessels, being the extreme ramifications of those which con- 

 veyed the blood from the right side of the heart to the 

 lungs, and the commencement of those which conduct it 

 back from the lungs to the left side of the heart. These 



