446 PHYSIOLOGICAL CHEMISTRY 



2. Guaiac Test. Place 5 c.c. of urine 1 in a test-tube and by means of a 

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

 i :6o) or the Lyle-Curtman 2 guaiac reagent (see p. 237) into the fluid until a 

 turbidity results, then add old turpentine or hydrogen 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 261 and test on page 265. 



3. Teichmann's Heroin Test. Place a small drop of the suspected urine or a 

 small amount of the moist sediment on a microscopic slide, add a minute grain 

 of sodium chloride and carefully evaporate to dryness over a low flame. Put a 

 cover-glass in place, run underneath it a drop of glacial acetic acid, and warm 

 gently until the formation of gas bubbles is observed. Cool the preparation, 

 examine under the microscope, and compare the form of the crystals with those 

 reproduced in Figs. 84 and 85, page 268. (See Nippe's modification, page 267.) 



4. Ortho-Tolidin Test (Ruttan and Hardisty). 3 To i c.c. of a 4 per cent 

 glacial acetic acid solution of o-tolidin 4 in a test-tube add i c.c. of the solution 

 under examination and i c.c. of 3 per cent hydrogen peroxide. In the presence 

 of blood a bluish color develops (sometimes rather slowly) and persists for some- 

 time (several hours in some instances). 



This test is said to be as sensitive for the detection of occult blood 

 in feces and stomach contents as is the benzidine reaction. It is also 

 cl imed to be more satisfactory for urine than any other blood test. 

 The acetic acid solution may be kept for one month with no reduction 

 in delicacy. 



5. Spectroscopic Examination. Submit the urine to a spectroscopic exami- 

 nation according to the directions given on page 300, looking especially for the 

 absorption bands of oxyhemoglobin and methemoglobin (see Absorption Spectra, 

 Plate I). 



6. Potassium Hydroxide Test (Heller). Render 10 c.c. of urine strongly alka- 

 line with potassium hydroxide solution and heat to boiling. Upon allowing the 

 heated urine to stand a precipitate of phosphates, colored red by the contained 



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

 is very sensitive to alkali. 



2 Lyle and Curtman: Jour. Biol. Chem., 33, i, 1918. 



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

 Bull., 2, 225, 1913. 



4 NH 2 NH 2 



C 6 H 4 -C 6 H 4 

 CH 3 CH 8 



