318 CONSTITUTIONAL DISEASES 



disease, show the effects of worry immediately, by the increase of the 

 amount of sugar, if sent away from their habitual surroundings. 



Diabetes Insipidus. 



This condition is a chronic one in which there is no elevation of 

 temperature, and a marked increase in the amount of clear urine secreted, 

 which is of a low specific gravity and contains no sugar. The animal is 

 constantly thirsty, drinking large quantities of water. This disease is 

 less frequently seen in the dog than diabetes mellitus and must not be 

 mistaken for ordinary polyuria which is seen where an animal drinks very 

 large quantities of water, or as a result of the administration of diuretics 

 or certain poisons or spices, or from atrophy of the kidneys after the 

 rapid reabsorption of extensive exudates or transudates. It is also seen 

 in a more or less pronounced degree in convalescence of an animal from 

 many acute diseases, and it is also observed in certain organic diseases 

 of the central nervous 'system. In this last group of sympathetic dia- 

 betes belong the case described by Holzmann; this dog was a very much 

 emaciated hound three years old, having a pale mucous membrane and 

 rectal temperature of 38.° The animal drank 12.57 c.c. of water daily, 

 and passed about 12.79 c.c. of urine. The urine was yellowish, had a 

 weak acid reaction, its specific gravity was l.OOG, and contained nothing 

 abnormal. On post-mortem nothing of any great consecjuence was 

 found, except a myxoma hyalinum, which appeared in the shape of a 

 yellowish, transparent, coagulated mass between the periosteum and 

 the dura mater, entirely surrounding the spine with the exception of a 

 small portion of the neck. There was also some hyperemia and slight 

 bleeding in the gray substance of the lumbar region. Five elongated 

 osteoid sarcoma masses were found pressing on the dura mater. Holz- 

 mann could not decide which of these two conditions was the true cause 

 of the disease. If we eliminate polyurias due to some organic alteration 

 of the cerebral nervous system, as a result of chronic interstitial inflamma- 

 tion of the kidneys, then polyuria is distinguished from diabetes insipidus 

 l)y the fact that the former is transitory in its character, and still it is 

 only by close observation, lasting for some time, that Ave can distinguish 

 between the two conditions; polyuria lasts only for a short interval 

 and does not produce any great tissue changes, whereas, diabetes insipi- 

 dus gradually progresses, becoming chronic, and is accompanied by 

 great emaciation. The urine is pale, of low specific gravity, and contrary 

 to chronic nephritis, contains no albumin. In all the cases observed by 

 the writer which he took at first for genuine diabetes insipidus, he 

 found where he could follow them closely, that after some time the 

 polyuria and increased thirst gradually disappeared. Schindelka de- 



