320 DIABETES IXSIPIDUS. 



period of twenty-four hours is not decreased, the quantity of 

 the secretion being sufficient, with even its relatively small 

 amount of solids, to bring the aggregate of these to the normal 

 standard, or even above it. 



When this condition exists as the direct result of causes 

 operating from Avithin, as consequent on some antecedent 

 disease, and coincident with excessive tissue-waste, and in 

 some cases with simply imperfect food-assimilation, the cha- 

 racter of the urinary secretion is chemically different ; it is less 

 watery, and instead of being pale, clear, and of less specific 

 gravity than natural, it is more or less coloured, thick, and of 

 a higher specific gravity. This physical and chemical alterna- 

 tion is probably dej^endent on the presence in the secretion 

 of a peculiar form of albumen, the product of the rapid and 

 excessive tissue-disintegration going on in the system. In 

 such cases the marasmus and general weakness are also 

 greater, and the chances of a fatal termination much in- 

 creased. 



Course and Termination. — In the greater number of cases of 

 polyuria, those which as a rule develop the milder form, and 

 in which the urinary secretion is abundant but of low specific 

 gravity, and where the solid and nitrogenous materials are 

 lessened in amount, the animal may suffer for a very length- 

 ened period before even any apprehensions of serious results 

 become fixed upon the minds of even well-informed attend- 

 ants or professional men. The conditions of polydipsia and 

 polyuria may continue for some time, and be well knoAvn, with- 

 out exciting much alarm ; but at length the muscular system 

 will show undue fatigue on moderate exertion, and cold 

 perspiration will break out over different regions of the body. 

 Languor and want of vivacity are soon followed by impaired 

 activity of the digestive and assimilatory processes, which, if 

 not arrested, speedily undermine the health, and ma}^ termi- 

 nate in structural changes of many organs. 



The earliest and most commonly encountered of these are 

 di'opsies and effusions in different cavities of the body, and in 

 the meshes of the interconnective-tissue where this is abund- 

 ant and lax in character. 



In that form Avlierc the products of excessive tissue-disinteg- 

 ration arc being passed oft" by the kidneys, the progress of the 



