244 MANUAL OF EQUINE MEDICINE. 



Section VI. 



DISEASES OF THE LIVER. 



GENERAL PHYSIOLOGICAL AND PATHOLOGICAL 



CONSIDERATIONS. 



Diseases of the liver are of far less frequent occurrence 

 in the horse than in man, but they are nevertheless of 

 great importance, owing to the many and varied functions 

 performed by this organ in health. 



The liver has at least three important functions. 



In the first place, it is concerned in the elaboration and 

 secretion of bile. Secondly, amyloid and saccharine sub- 

 stances, brought to it by the portal vessels from the alimen- 

 tary canal, are converted into glycogen. 



Glycogen (CgHjoOg), or animal starch, is a substance re- 

 sembling dextrin, and is similarly convertible into sugar 

 by the action of albuminoid ferments. It is formed and 

 stored up in the hepatic cells, whence it is removed as re- 

 quired by the hepatic veins, and is thus distributed through- 

 out the system to be used as required. 



It is used partly for the maintenance of the bodily heat, 

 which is generated during its oxidization into carbonic acid 

 and water, and partly to take an important share in the 

 growth, development, and functional activity of cells, and 

 also probably in the development of the blood corpuscles. 



Glycogen is in all probability convertible into fat in the 

 system. 



Thirdly, the liver is concerned in the reduction of various 

 albuminous matters brought to it into simpler compounds. 



The latter include glycogen, leucin, tyrosin, uric acid, 

 hippuric acid, and urea. 



Of the clinical features of hepatic disease, jaundice, local 

 pain in the region of the liver, manifestation of colicky pain, 



