XVI. 



THE URINE. 



105 



2. Quantity. Normal. About i\ pints (50 ounces) or 1500 

 cc. in twenty-four hours, although there may be a considerable 

 variation even in health, the quantity being regulated by the 

 amount of fluid taken, and controlled by the state of the tissues, 

 tlio pulmonary and cutaneous excretions. 



Collection. It should be collected in a tall graduated glass 

 cylinder of a capacity of 2500 cc. with a ground glass top to 

 exclude impurities. Samples of the mixed urine of 

 the 24 hours are used for examination. 



Increased by drinking water (tirina potus] or diuretics ; when 

 the skin is cool, its blood-vessels are contracted, and the cutaneous 

 secretion is less active ; after a paroxysm of hysteria, and some 

 convulsive nervous diseases ; in diabetes insipid us and d. mellitus; 

 some cases of hypertrophy of the left ventricle, and some kidney 

 diseases. The increase may be temporary or persistent, the 

 former as the effect of cold, diuretics, or nervous excitement ; 

 the latter in diabetes and certain forms of kidney-disease. 



Diminished after profuse sweating, diarrhoea ; early stage of 

 acute Bright's disease ; some forms of Bright's disease , the 

 last stages of all forms of Bright's disease ; in general dropsies ; 

 in acute febrile and inHammatory diseases. 



3. Colour. Normal. Light-straw to amber-coloured. 

 The colour varies greatly even in health, and is due 

 to the presence of a mixture of pigments, probably 

 largely derived from the decomposition of haemoglobin. 

 Of these pigments urobilin, an iron-free derivative of 

 lib', is the chief. The colour largely depends on the 

 degree of dilution of the urine pigments. 



Pale after copious drinking, in diabetes, anaemia, and chlorosis; 

 after paroxysmal nervous attacks (hysteria). N.B. Pale urines 

 indicate the absence of fever. 



High-coloured after severe sweating, violent muscular exercise, 

 diarrhoea, or during febrile conditions. 



Pathological pigments, purptirine or uro-erythrine in febrile 

 disorders ; bile pigments ; blood. 



Medicinal Substances. Creosote and carbolic acid make urine 

 nearly black. This is due not to carbolic acid, but to hydro- 

 chinon. Sometimes these urines become almost black on stand- 

 ing exposed to the air. Rhubarb (gamboge-yellow) ; senna 

 (brownish). 



1000 

 1010 



mo 



1030 

 _1040 



FlO. 52. 



4. Specific Gravity. Normal, s.g. 1020 (1015- unnometer. 

 1025). This is taken by- means of the urinometer 

 (fig. 52). The instrument ought to be tested by placing it in a 

 cylindrical vessel filled with distilled water to ascertain that its 

 zero is correct. 



(a.) Fill a tall cylindrical vessel with urine, and place the 



