43 PHYSIOLOGICAL CHEMISTRY 



reproduced in Figs. 78 and 79, page 265. (See Atkinson and Kendall's and 

 Nippe's modifications, page 264.) 



3. Heller-Teichmann Reaction. Produce the pigmented precipitate according 

 to directions given in Heller's test above. If there is a copious precipitate of phos- 

 phates and but little pigment the phosphates may be dissolved by treatment with 

 acetic acid and the residue used in the formation of the hemin crystals according 

 to directions in Experiment 2, above. 



4. v. Zeynek and Nencki's Hemin Test. To 10 c.c. of the urine under examina- 

 tion add acetone until no more precipitate forms. Filter off the precipitate and 

 extract it with 10 c.c. of acetone rendered acid with 2-3 drops of hydrochloric acid. 

 Place a drop of the resulting colored extract on a slide, immediately place a cover- 

 glass in position, and examine under the microscope. Compare the form of the 

 crystals with those shown in Figs. 78 and 79, page 265. Hemin crystals produced 

 by this manipulation are sometimes very minute, thus rendering it difficult to de- 

 termine the exact form of the crystal. 



6. Guaiac Test. Place 5 c.c. of urine in a test-tube and by means of a 

 pipette introduce a freshly prepared alcoholic solution of guaiac (strength about 

 i : 60) into the fluid until a turbidity results, then add old turpentine or hydro- 

 gen peroxide, drop by drop, until a blue color is obtained. 



This is a very delicate test when properly performed. Buckmaster 

 has suggested the use of guaiaconic acid instead of the solution of 

 guaiac. The test is positive both before and after boiling the blood 

 for 15-20 seconds. Pus does not respond after boiling. Old, partly 

 putrefied pus gives the test even without the addition of hydrogen 

 peroxide or old turpentine whereas fresh pus responds upon the addition 

 of hydrogen peroxide. See discussion on page 258 and test on page 262. 



7. Schumm's Modification of the Guaiac Test. To about 5 c.c. of urine 1 in a 

 test-tube add about 10 drops of a freshly prepared alcoholic solution of guaiac. 

 Agitate the tube gently, add about 20 drops of old turpentine, subject the tube to 

 a thorough shaking, and permit it to stand for about 2-3 minutes. A blue color 

 indicates the presence of blood in the solution under examination. In case there 

 is not sufficient blood to yield a blue color under these conditions, a few cubic centi- 

 meters of alcohol should be added and the tube gently shaken, whereupon a blue 

 coloration will appear in the upper alcohol-turpentine layer. 



A control test should always be made using water in place of urine. In the 

 detection of very minute traces of blood only 3-5 drops of the guaiac solution should 

 be employed. 



8. Ortho-Tolidin Test (Ruttan and Hardisty). 2 To i c.c. of a 4 per cent 

 glacial acetic acid solution of o-tolidin 3 hi a test-tube add i c.c. of the solution 



1 Alkaline urine should be made slightly acid with acetic acid as the blue end-reaction 

 is very sensitive to alkali. 



2 Ruttan and Hardisty: Canadian Medical Assn. Journal, Nov., 1912, also Biochemical 

 Bull., 2, 225, 1913. 



3NH 2 NH 2 



C 6 H 4 - C 6 H 4 

 CH 8 CH 3 



