URINE. 183 



Mucus frequently accompanies sediments of the urates and 

 earthy phosphates, and its presence in these cases may be de- 

 tected by the microscope. When mucus is separated in large 

 quantity, (as in vesical catarrh,) carbonate of ammonia is soon 

 formed, and we always find numerous crystals of ammoniaco- 

 magnesian phosphate. 



The quantitative estimation of the mucus must be effected in 

 the manner described in page 135. The ratio of its weight to 

 that of the solid constituents must be determined. 



In order to ascertain the quantity of mucus in a sediment of 

 urates and earthy phosphates, the sediment must be collected, 

 the urates dissolved in hot water, and the earthy phosphates 

 then taken up by acidulated water. The mucus will remain on 

 the filter, and must be dried and weighed. 



The method of conducting the quantitative analysis of diseased 

 urine is precisely the same as for the healthy secretion, provided 

 the changes are only dependent upon an increase or diminution 

 of one or more of the normal constituents : indeed it may be 

 still more simplified by omitting the exact determination of 

 the lactic acid, the lactates, the chloride of ammonium, and the 

 extractive matters. 



The proportions of water and of solid residue must be de- 

 termined, in the manner already described, from a weighed 

 quantity of filtered urine. The residue, after being dried over 

 sulphuric acid, must be moistened with a little warm water, 

 and then thoroughly extracted with anhydrous alcohol. The 

 undissolved portion must be dried, weighed, and incinerated. 

 The extractive matters and uric acid are consumed, and there 

 remain the earthy phosphates, the alkaline sulphates and phos- 

 phates, and the chloride of sodium, which must be separated 

 and determined. 



The anhydrous alcoholic solution must be gently evaporated, 

 dried over sulphuric acid, weighed, and dissolved in a little 

 water. The urea must be then precipitated as a nitrate, which 

 must be separated and dried in the ordinary manner, weighed, 



