DISEASES OF THE URINARY ORtiANS. 1,39 



SACCHARINE DIABETES (DIABETES MELLITUS, GLYCOSURIA, OR 



INOSURIA). 



This is |)riin:ii-ily a tlist'iise of tlu' iktvous systt'iu or Iimt ratluT 

 than of the kichievs. yet, as the most prominent symptom is the sweet 

 mine, it may be treated here. 



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

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

 l)rominent functions of the liver is the formation of glycogen, a prin- 

 ci[)le 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, Avhen 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 quantity of sugar produced is 

 more than can be disposed of in the natural way, and it appears in the 

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

 hearty meal on starchy feed, but this is due altogether to the super- 

 abundant supply of the sugar-forming feed, lasts for a few hours 

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

 glycosuria the liver is found to l)e enlarged, or at least congested, and 

 it is found that the disorder can be produced experimentally by 

 agencies which produce an increased circulation through the liver. 

 Thus Bernard produced glycosuria by pricking the oblong medulla at 

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

 which happens to be also the nerve center (vasomotor) which presides 

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

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

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

 j)neumogastric nerve causes saccharine urine, and, in keeping with 

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

 ])lete removal of the pancreas, however, determines glycosui'ia, the 

 oi-gan having in health an iiihibitive action on sugar pi-oduction by 

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

 (»ther sources, as from diflerent ganglia (coij)ora striata. optic thalami, 

 j)ons, cerebellum, cerel)rum) of the l)rain. .Similarly it is induced by 

 interruption of the nervous control along the vasomotor tracts, as in 

 destruction of the upper oi' lower cei'vical sympathetic ganglion, by 

 cutting the nervous liranch connecting these two, in injury to the 

 spinal mariow in the interval between the brain and the second or 

 fourth dorsal vertel)ra, or in disea.se of the celiac plexus, which 

 directly presides over the liver. Certain chemical poisons also cause 

 saccharine urine, notably woorara. strychnia, morphia, phosphoric 

 acid, alcohol, ether. (|uinia. chloroform, ammonia, arsenic, and 

 phlorizin. 



