THE URINE. 215 



thelial scales ; these do not form part of the urine, but belong 

 to the structure of the mucous membrane of the bladder and 

 urethra, and both of them may be detected with the greatest 

 facility by the microscope. On account of their greater 

 specific gravity, they subside at the bottom of the vessel 

 containing the urine, where they may, at most times, be 

 procured for examination. 



Occasionally, however, in the urine of man, under the cir- 

 cumstance already referred to in the article on the semen, the 

 spermatozoa are present in the urine also. 



PATHOLOGY OF THE URINE. 



The organic principles contained in diseased urine may be 

 divided, firstly, into those which are usually encountered in 

 that fluid in a state of solution, but which do yet, under 

 certain circumstances, assume the solid form ; and secondly, 

 into those which being definite organisms, occur only in a 

 solid condition. Albumen, fibrin, casein, and fat, belong to 

 the first, and the blood and pus corpuscles to the second 

 division. 



Albuminous Urine. 



Albumen is frequently present in the urine in disease ; it 

 has been noticed to occur especially in Bright's disease of the 

 kidney, and in the urine passed after scarlatina. 



If the albumen be present in any considerable quantity, 

 nitric acid or bichloride of mercury will cause a precipitate, 

 and the urine will become turbid on the application of heat, 

 and deposit flocculi of coagulated albumen. 



The colour, specific gravity, and reaction of albuminous 

 urine are various ; thus it may be either light or dark coloured, 

 it ma^ be of high or low specific gravity, it may exhibit either 

 an acid or an alkaline reaction, or it may be neutral. 



When the albumen is small in quantity, heat is the most 

 efficient test for its detection ; it is only when the urine 

 manifests a decided alkaline reaction, that nitric acid is pre- 



