86 MIDRIFF, ITS USES. [BOOK I. 



artery which carry on the circulation of the blood 

 of the hinder part. With these exceptions it is 

 air-tight, and it bears resemblance to the head of a 

 drum in another particular — it is membranous, ex^ 

 cept round the edge next to the ribs, &c. where it 

 is found somewhat fleshy. From its situation in 

 the middle, this natural division is termed the mid- 

 riff, its edge is the skirt, and appears to have been 

 designed for keeping back the stomach and bowels 

 of the hinder part, which as it is, when full, press 

 it out of shape, not unlike that of a watch glass, 

 and would, but for this barrier, interrupt the action 

 of the heart and lungs. But by the present con- 

 trivance, as we shall see presently, this pressure 

 from behind soon recedes, the midriff returns to its 

 level, and the ribs, no longer contracted towards 

 each other by the aforesaid pressure, expand, there- 

 by enabling the lungs to perform their function of 

 drawing in a fresh supply of air. Upon this prin- 

 cipal agent in the function of respiration see more 

 detail in the 35th. section. 



26. After this necessary preamble, let us proceed, 

 as before proposed, to consider the construction of 



The Membranes, 

 Muscles, 

 Glands, 

 Absorbents (of two kinds, 1st lymphatics, 



and 2d lacteals), 

 Nerves *. 



* For ligaments, cartilages, tendons, &c. see sections \G, 17- I» 



