920 Diabetes Insipidus. 



of water for the elimination of solid urinary constituents, primarily 

 of urea and sodium chloride, or the kidneys have lost the faculty to 

 reabsorb the water secreted into the glomeruli. 



Anatomical Changes. The autopsy findings are sometimes 

 entirely negative; in other cases changes are found in the 

 central nervous system (in Holzmann's case the spinal cord 

 of a dog was surrounded in almost its entire length by myxoma- 

 tous tissue and several dural sarcomas) or signs of an earlier 

 general affection, as well as secondary changes in the organ. 

 The kidneys are either entirely normal or show only unim- 

 portant changes (cloudy swelling, hyperemia, etc.). 



Symptoms. After feeding mouldy oats or other spoiled 

 fodder the symptoms develop in a short time, sometimes within 

 3 to 5 days. In other cases the evolution is gradual so that 

 the disease is only suspected from the striking emaciation 

 and debility. 



The most essential and important symptom consists in a 

 decided increase in the amount of urine. The animals secrete 

 large quantities of urine at brief intervals, the total amount 

 in 24 hours being several times the normal daily output, so 

 that horses may pass as much as 40 to 60 liters, dogs 3 to 4 liters. 

 The urine is watery, without odor, of very low specific gravity 

 which may be continuously around 1.001-1.002. Foreign con- 

 stituents, especially albumen and sugar, , cannot be found and 

 microscopical examination in this direction is also negative. 

 While the urine is usually voided easily, this may later on be- 

 come somewhat painful because of catarrhal swelling of the 

 urethral mucous membrane. 



A second symptom, which is never absent, is a considerably 

 increased thirst (polydipsia) which causes the animals to drink 

 surprising amounts, horses as much as 100 liters of water, dogs 

 up to 10 or 15 liters per day, and if the water is not given 

 them in sufficient amounts, they will drink even bad and ill- 

 smelling water, as well as their own urine. The amount of 

 urine corresponds to the amount of water ingested either alone 

 or with the food, or it exceeds it at most only transitorily. 

 (The idea that the skin and the mucous membranes of diabetics 

 can absorb water from the air lacks all foundation.) Com- 

 parative researches have proved that with an equal ingestion 

 of water the diabetic organism secretes more urine than the 

 healthy. 



The appetite varies greatly. At first the animals take 

 palatable fodder willingly, but later they refuse even this or 

 eat only a little from time to time. The mucous membranes 

 and the skin become dry, the hair dull and coarse. Schindelka 

 observed in a dog cataract, abscess formation in the perianal 

 glands and in the prostate. Sooner or later emaciation Com- 

 mences and may increase either gradually or rapidly. 



