113 



cal shape without, and, within it, the kings taken 

 as a whole form a soii; of cone, the apex of which 

 is above, while the base rests on the diaphragm 

 below. 



The shape of the four incased parts, which are 

 put together to form the cone, may perhaps be best 

 given by supposing first, a perpendicular plane 

 passed lengthwise through the spine and the breast 

 bone, this will divide the lungs into right and left 

 halves. Then another plane, oblique from above 

 downwards its upper surface facing to the front, 

 passed between the true and the false ribs, will 

 divide the whole into four pieces, which are called 

 " lobes,'' and the general shape of each of the four 

 will be given by the direction of the planes. 



§ 112. To each of the two upper lobes of the 

 lungs appendages are added, at their upper ends, 

 which may be called "tips ;"^ when unfilled these lie 

 somewhat bent and twisted, at the summit of each 

 lung. As we suppose every part of the lung to 

 fill, not always in the same order, but according as 

 the movements of the chest create a vacuum, these 

 tips would, on our theory, fll from above doivn- 

 ward, i. e., in the opposite direction to the filling 



* That these ''Tips " may have some special action, is alluded to in 

 an article in '' Townsend's Cyclopajdia of Anatomy." 



