270 MANUAL OF MODERN FARRIERY. 



the belly, and is reflected upon the contained viscera. It 

 presents a shining secreting surface, of a whitish aspect, and 

 considerable transparency. Its internal surface is smooth 

 and humid. The use of this organ is to secrete a serous 

 fluid, which is intended for lubricating every part of the 

 membrane, in consequence of which those viscera that are 

 continually moving within the belly glide over one another, 

 not only without friction, but without exciting the least 

 consciousness of their motions on the part of the animal 

 himself. In addition to this, the peritoneum furnishes most 

 of the viscera with a complete external tunic, and thereby 

 adds strength and firmness to their several textures. It 

 attaches, supports, and confines those viscera (within certain 

 limits) in their respective places ; and it strengthens the 

 abdominal cavity altogether by its uninterrupted extension 

 everywhere through and around it. 



THE DIAPHEAGM. 



PLATE IX. Fig. 1., h. 



This forms a fleshy and tendinous partition, dividing the 

 cavity of the chest from that of the abdomen. It is of a 

 broad circular form, flattened from before backwards ; its 

 front surface is convex, and concave behind ; divided or 

 forked above, and having two elongations or appendices ex- 

 tending backwards, with pointed extremities. On that side 

 next the chest it is invested by the membrane which covers 

 the lungs, and towards the belly by that which covers the 

 intestines. It adheres to the spine, the ribs, and the breast- 

 bone, by strong muscular fibres. Its structure is fleshy and 

 tendinous. The fleshy parts are those which form the cir- 

 cumfercnt portions of the large muscle, and the principal 

 part of the crura or appendices. The tendinous parts con- 



