URINE. 289 



emission, it is ammoniacal, and of an unpleasant odour. The 

 pus is sometimes mingled with blood. That the clear filtered 

 urine always contains albumen may be shown by the addition 

 of nitric acid, or by the application of heat. 



The urine immediately on its discharge is turbid, but on being 

 allowed to rest, the pus separates in a clearly-defined layer at 

 the bottom ; on shaking, it easily mixes again with the urine, 

 and if that fluid have an alkaline reaction the pus becomes 

 tough and fibrous. Pus-corpuscles may be detected by the 

 microscope, and if the urine has an alkaline reaction they will 

 be mixed with crystals of the ammoniaco-magnesian phosphate 

 and with an amorphous precipitate of phosphate of lime. 



In order to determine with certainty whether a urinary sedi- 

 ment consists of mucus or of pus, urine which has been just 

 discharged should be examined : the rapid descent of the pus- 

 corpuscles from urine which is turbid at the period of its dis- 

 charge, and the formation of a sediment which is frequently 

 discoloured, or mixed with blood, together with the presence of 

 a considerable amount of albumen in the urine, leave no doubt 

 respecting the diagnosis. (See page 202.) 



Diabetes mellitus. 



In diabetes mellitus it is well known that the urine undergoes 

 a very peculiar change ; it contains a certain quantity of sugar 

 which, in its ultimate constitution is perfectly identical with 

 grape-sugar, and in consequence of which the urine possesses 

 the property of deflecting the polarized ray to the right. Dia- 

 betic urine differs moreover in its physical relations from the 

 normal secretion ; it is paler, has a turbid wheyish appearance 

 with a greenish tinge, and a higher specific gravity, according 

 to Willis, from 1025 to 1055. 



Henry drew up a table for the determination of the solid 

 constituents of diabetic urine by the mere application of the 

 urinometer. The results, as far as my experience goes, come 

 sufficiently near to the truth to give fair approximate values to 

 the solid residue from the specific gravity. G. O. Rees recom- 

 mends the table, having confirmed it by his own experiments ; 

 I have somewhat extended its limits, and shall give it here. 



ii. 19 



