190 THE SECRETIONS: 



in the other case, we observe an amorphous granular matter. 

 Cases have however occurred in which the urine has contained 

 so large a quantity of fat that the oil-vesicles could be observed 

 even with the naked eye, and formed a perfect stratum on the 

 surface; such cases have been recorded by Elliotson and 

 Bachetoni. 1 



The microscope is always sufficient for the recognition of fat 

 in urine. If a quantitative determination of the fat is required, 

 a weighed portion of urine must be evaporated and the residue 

 repeatedly extracted with ether. The ether must then be eva- 

 porated, and the fat separated from the urea, and other con- 

 stituents which may have been also taken up by means of water. 

 This separation should be effected in a small porcelain basin, 

 in which the fat must be heated till all aqueous moisture is dis- 

 sipated, and then weighed. If the amount of solid residue is 

 known either by this, or a separate experiment, the proportion 

 of fat to the urine, and to the solid residue, can be at once 

 obtained. The residue, after the separation of the fat, will 

 serve for the determination of other constituents, as urea or 

 extractive matters; it must however be remembered that the 

 water in which the fat was washed, contains some little urea. 



Chylous urine. Chylous urine contains both fat and albu- 

 men; it is usually turbid, curdy, sometimes even resembling 

 milk in point of colour. Under the microscope it exhibits 

 numerous fat-vesicles. On the addition of a small quantity of 

 acetic, or dilute sulphuric or hydrochloric acid, no coagulation 

 occurs, even when gentle heat is applied ; but on the addition 

 of nitric acid a white precipitate is observed. Upon the ap- 

 plication of heat to chylous urine, the albumen coagulates in 

 flocculi. The methods of determining the amount of albumen 

 and fat have been already given. 



5. Casein. 



Casein has never yet, so far as I know, been observed as a 

 single extraneous constituent of the urine, as albumen some- 

 times seems to occur, but has always been found in combination 

 with fat, and, in all probability, also with sugar, forming milky 

 urine. 



1 Urinary Diseases and their Treatment. By Robert Willis, M.D. p. 166. 



