ABDOMEN. 



193 



piece of the body is divided by the diaphragm into two 

 portions, the chest and abdomen ; the former containing the 

 lungs and heart ; the latter, the stomach, liver, intestines, 

 bladder and other organs. The ribs form the walls of the 

 chest. The contents of the belly (consisting mostly of the 

 intestines) are kept in their place chiefly by powerful ligaments, 

 the principal one of which is the abdomi7ial hmic {see p. 

 34), and by muscles. These structures are respectively 

 attached to the margin of the front part of the pelvis, to the 

 rear part of the breast bone, rearmost edge of the ribs, and to 

 the sides of the loin vertebrae, thus bridging over the vacant 

 space. We may, then, fairly assume that the abdomen should 

 follow the general contour of the chest. As the straight 

 muscle of the abdomen which covers the lower portion of this 

 cavity, is the chief muscle that bends the back, the horse can- 

 not be thoroughly " fit " for work, if this muscle is unduly 

 pressed down by the intestines. We may also conclude that, 

 when a horse has a naturally pendulous belly, he will be 

 wanting in quickness and stamina, which cannot be possessed 

 without the ability to freely move the spine. This and the 

 other muscles of the abdomen aid in the process of breathing, 

 which will be more or less interfered with, if these muscles 

 have to constantly strive against undue pressure from the 

 cavity they cover. Besides this, if the intestinal mass is 

 greater than it ought to be, it will hamper the action of the 

 lungs by forcing the diaphragm too far into the chest ; it 

 will add to the weight to be carried ; and will militate against 

 speed by tending to bring the centre of gravity to the 

 rear {see p. 51). Although the subject of feeding is not 

 within the province of this book, it may not be out of place 

 if I mention that the practice of giving horses large quantities 



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