32 



ANATOMY. 



reflected upon them at their roots, so that each lung is really outside 

 the sac of its pleura, the moist inner surfaces of which touch each 

 other, the lungs everywhere filling up their own compartments of the 

 thorax. In the root of each lung is found a branch of the windpipe, 

 certain large bloodvessels, other smaller ones, with absorbents and 

 nerves. 



Between the two pleural sacs is a space called the mediastinum, in 



Fig. 13. 



Fig. 13. Front view of the cavities of the thorax and abdomen, laid open by removal of their anterior 

 walls. The tip of the sternum, and part of the cartilages of the seventh and following ribs, are preserved, 

 as the diaphragm which separates these two large cavities of the trunk is fixed to them. In the thorax 

 are seen the right and left lungs, 1 1, occupying each its own compartment; and between them the peri- 

 cardium, or bag of the heart, laid open to show a part of that organ, h. Passing up from the heart to the 

 sides of the neck are the great bloodvessels, the aorta *, the vein i, between which are seen the windpipe, 

 larynx, and pharynx. Below the diaphragm, and therefore in the abdomen, is seen, projecting below the 

 right ribs, a part of the liver, a, crossed by a white line, which is the cut edge of its broad ligament: from 

 a notch low down projects the gall bladder. Under the liver, and to the left is the stomach, s, at the left 

 end of which is seen a piece of the spleen; below it is the transverse part of the great intestine, or trans- 

 verse colon, c, ending on the right side below the liver, in the ascending colon, and on the left in the de- 

 scending colon. Occupying the middle of the abdomen are the coils or convolutions of the small intestines. 

 Lowest of all is the top of the urinary bladder. (After Bourgery.) 



which many parts are found. The chief of these is the heart, Figs. 

 18 and 14 h. This organ is inclosed in a distinct fibrous bag or sac, 



