350 DISEASES OF METABOLISM 



of some value, tincture nux vomica (0.3 to 0.6), once or 

 twice daily. 



Diabetes Mellitus.— Definition.— Diabetes mellitus is a 

 chronic, nutritive disorder in which grape-sugar accumulates 

 in the blood and is excreted in the urine. The condition may 

 be permanent or occur periodically. It is generally con- 

 sidered that in order for a case to be true diabetes mellitus, 

 the sugar eliminated must be grape-sugar, and it must extend 

 over a rather long period of time. 



Occurrence.— The disease is not very common in animals. 

 A few cases have been found in dogs. The cat and rabbit 

 are very seldom affected. 



Etiology.— The exact etiology of diabetes mellitus is not 

 known. It is quite evident that several factors may have to 

 do with the production of the disease. Nervous diseases, 

 especially those of the central nervous system, and diseases 

 of the liver and pancreas probably produce the larger number 

 of cases. The pathogenesis of diabetes mellitus is not quite 

 clear, but the condition may be brought about by a disturb- 

 ance of the liver or pancreas, in which the grape-sugar taken 

 into the body is not converted into glycogen but taken up as 

 grape-sugar by the circulation and eliminated in this form. 



Pathology.— Many cases present no anatomical changes. 

 There may be hemorrhages in the nervous system, tumor 

 formations, etc. Very often fatty degeneration of the liver 

 is present. The pancreas may be enlarged by connective 

 tissue proliferation and an atrophy of the glandular substance. 

 The other structures show emaciation and evidences of 

 cachexia due no doubt to the chronicity of the disease. 



Symptoms.— Until the patient shows emaciation, notwith- 

 standing good appetite, the disease is usually not recognized. 

 The general symptoms are: The animal fatigues easily, 

 becomes dull and listless and does not move about in a normal 

 way, shows increased thirst and appetite. The mucous 

 membrane of the mouth becomes dry, and gingivitis is often 

 present. The most characteristic symptoms are found in 

 connection with the urinary organs. The urine is increased 

 in amount, sometimes double the normal quantities voided, 

 is pale, colorless, of a sweetish odor (aceton) and acid in 



