EXAMIXATION OF THE URINE 179 



from calcium oxalate, and occur in large quantities in chronic cystitis. 

 There are a numl_)er of abnormal substances found in the urine. The 

 principal ones are albumin, sugar, and the coloring substances of the 

 bile. 



i. Albumin. — The presence of albumin in the urine is always an 

 indication of disease. The two most important forms of albumin are 

 serum-albumin and serum-globulin; the two are generally in combina- 

 tion, and both give the same reaction. 



Fig. 80.— Urine of a dog with cystitis, triple phosphate crystals, red and white blood corpuscles, and 



cystic epithelium. Bacteria. 



Koch's Test. — The urine to be examined must be carefully filtered 

 before proceeding with the test. The urine is boiled in a test-tube, hav- 

 ing been previously rendered acid in reaction by the addition of a small 

 quantity of acetic acid. The urine may become opaque from two causes; 

 from the presence of albumin or from phosphates; to this we add nitric 

 acid drop by drop until the phosphate is all dissolved and the albumin 

 remains opaque. 



Heller's Test. — The urine is rendered acid; then pour a small quan- 

 tity of nitromuriatic acid down the side of the tulje, and if there is any 

 albumin present there will be a pronounced opaque ring or line where 

 the acid meets the urine. 



Test with Acetic Acid and Ferrocyanide of Potassium. — The urine is 

 rendered acid with acetic acid and drop by drop a 5 to 10 per cent, solution 

 of ferrocyanide of potassium is added; if albumin is present, a white 

 turbidity indicates the presence of albumin. If the solution immedi- 

 ately becomes turbid on the addition of a very small quantity of the solu- 

 tion it is due to the presence of mucin and must be filtered immedi- 

 ately before proceeding. Very concentrated urine must be diluted with 

 a certain quantity of water. The quantitative test for albumin must 

 be made by means of an albuminometer; if this is required the methods 

 described in text-books on analytical chemistry should be consulted; as 

 a rule the simple proof of the presence of albumin is sufficient for diag- 

 nostic purposes. 



