MICROSCOPICAL DIAGNOSIS. 47 



heat-test ; if it be not already acid it can be made so easily 

 by adding ten or fifteen drops of nitric acid to the drachm 

 of urine. It should be borne in mind that if a very little 

 nitric acid be added to albuminous urine and heat applied, no 

 precipitate of albumen will occur ; the nitric acid should be 

 added in excess, ten or fifteen drops to the drachm of urine. 



Some of the resinous matters, as cubebs, turpentine, etc., 

 might be mistaken for albumen. These are differentiated from 

 albumen by adding some alcohol to the specimen ; if the tur- 

 bidity disappears by so doing, it denotes the presence of these 

 resinous matters. 



The microscope is of aid in examining the following : 



First. Substances that float on the surface of,J the urine or 

 are diffused through it. 



Second. Light and flocculent deposits. 



Third. Dense and opaque deposits. 



Fourth. Crystalline and granular deposits. 



Belonging to the first-class are the fatty matters found in 

 the urine. Fatty matters often get into the urine accidentally, 

 however it may be found in the molecular state as in chylous 

 urine ; or in the form of oil globules in cases of fatty degen- 

 eration of the kidneys ; or it may be found in casts. Beale 

 reports cases where cholesterine was found in the urine with the 

 fatty matter which passes in fatty degeneration of the kidneys. 

 The crystals of cholesterine are rectangular or rhomboidal, very 

 thin and transparent, with regular borders, and frequently mark- 

 ed by a break at one corner. The crystals have a great ten- 

 dency to break in parallel lines ; this property with their trans- 

 parency and the parallelism of their borders renders these crys- 

 tals very characteristic. 



THE LIGHT AND FLOCCULENT DEPOSIT. 



Mucus. This is observed in healthy urine, after it has been 

 allowed to stand a few hours, as a bulky, flocculent deposit, 

 which shows under the microscope a few granular, circular 

 cells, not unlike the white corpuscles of the blood, and a trans- 

 parent substance which may show a few very thin interlacing 

 fibrils. 



Spermatozoa. These are easily recognized by their char- 



