80 BUREAU OF ANIMAL INDUSTRY. 



SACCHARINE DIAB"f:TES (dIABETES MELEITUS, GLYCOSURIA, OR INOSURIA). 



This is primarily ii disease of the nervous system or liver rather 

 than of the kidneys, yet, as the most prominent symptom is the sweet 

 urine, it may be treated here. 



Causes. — Its causes are varied, but resolve themselves largely into 

 disorder of the liver or disorder of the brain. One of the most 

 prominent functions of the liver is the formation of glycogen, a prin- 

 ciple allied to grape sugar, and passing into it by further oxidation in 

 the blood. This is a constant function of the liver, but in health the 

 resulting sugar is burned up in the circulation and does not appear in 

 the urine. On the contrary, when the supply of oxygen is defective, 

 as in certain diseases of the lungs, the whole of the sugar does not 

 undergo combustion and the excess is excreted by the kidneys. Also 

 in certain forms of enlarged liver the amount of sugar produced is 

 more than can be disposed of in the natural wa}', and it appears in the 

 urine. A temporary sweetness of the urine often occurs after a 

 hearty meal on starch}- food, but this is due altogether to the super- 

 abundant suppl}^ of the sugar-forming food, lasts for a few hours 

 only, and has no pathological signilicance. In many cases of fatal 

 glj-cosuria the liver is found to be enlarged, or at least congested, and 

 it is found that the disorder can be produced experimentall}^ by 

 agencies which produce an increased circulation through the liver. 

 Thus Bernard produced glycosuria by pricking the oblong meduUa at 

 the base of the brain close to the roots of the pneumogtistric nerve, 

 which happens to be also the nerve center (vaso-motor) wdiich presides 

 over the contractions of the minute blood vessels. The pricking and 

 irritation of this center leads to congestion of the liver and the exces- 

 sive production of sugar. Irritation carried to this point through the 

 pncumogastric nerve causes saccharine urine, and, in keeping with 

 this, disease of the pancreas has been found in this maladj^. The com- 

 plete removal of the pancreas, however, determines glycosuria, the 

 organ having in health an inhilntive action on sugar production by 

 the liver. The same result follows the reflection of irritation from 

 other sources, as from different ganglia (corpora striata, optic thalami, 

 pons, cerebellum, cerebrum) of the brain. Similarly it is induced by 

 interruptiu' of the nervous control along the vaso-motor tracts, as in 

 destruction of the upper or lower cervical S3'mpathetic ganglion, by 

 cutting the nervous branch connecting these two, in injurj^ to the 

 spinal IT. irrow in the interval between the brain and the second or 

 fourth dorsa^ vertebra, or in disease of the celiac plexus, which 

 directly presides over the liver. Certain chemical poisons also cause 

 saccharine urine, notably woorara, strj^chnia, morphia, phosphoric acid, 

 alcohol, ether, quinia, chloroform, ammonia, arsenic, and phlorizin. 



Symj)toms. — The symptoms are ardent thirst and profuse secretion 



