BLOOD PIGMENTS. H^MATOPORPHYRIN. 797 



taining pus, even when no blood is present, gives a blue color with these 

 reagents; but in this case the tincture of guaiac alone, without tur- 

 pentine, is colored blue by the urine (VITALI 1 ). This is at least true 

 for a tincture that has been exposed for some time to the action of air 

 and sunlight. The blue color produced by pus differs from that pro- 

 duced by blood-coloring matters by disappearing on heating the urine 

 to boiling. A urine alkaline by decomposition must first be made faintly 

 acid before performing the reaction. The turpentine should be kept 

 exposed to sunlight, while the tincture of guaiac must be kept in a 

 dark glass bottle. These reagents to be of use must be controlled by a 

 liquid containing blood. With positive results, however, this test is 

 not absolutely decisive, because other bodies may give a similar reaction, 

 but when properly performed it is so extremely delicate that when it 

 gives negative results any other test for blood is superfluous. 2 



As the delicacy of the above-mentioned tests is sufficient for ordinary 

 purposes it is not necessary to give the new blood-tests suggested recently. 



HELLER-TEICHMANN'S Test. If a neutral or faintly acid urine containing 

 blood is heated to boiling, one always obtains a mottled precipitate consist- 

 ing of proteid and haematin. If caustic soda is added to the boiling-hot test, 

 the liquid becomes clear and turns green when examined in thin layers (due to 

 haematin alkali), and a red precipitate, appearing green by reflected light, re-forms, 

 consisting of earthy phosphates and haematin. This reaction is called HELLER'S 

 blood-test. If this precipitate is after a time collected on a small filter, it may be 

 used for the hsemin test (see page 293). If the precipitate contains only a little 

 blood-coloring matter with a larger quantity of earthy phosphates, then wash 

 it with dilute acetic acid, which dissolves the earthy phosphates, and use the 

 residue for the preparation of TEICHMANN'S haemin crystals. If, on the contrary, 

 the amount of phosphates is very small, then first add a little MgCk solution 

 to the urine, heat to boiling, and add simultaneously with the caustic potash 

 some sodium-phosphate solution. In the presence of only very small quantities 

 of blood, first make the urine very faintly alkaline with ammonia, add tannic 

 acid, acidify with acetic acid, and use this precipitate in the preparation of the 

 haemin crystals (STURVE 3 ). 



0. and R. ABLER 4 have recommended leucomalachite green or benzidine in 

 the presence of peroxide and acetic acid as especially sensitive reagents for blood. 



Haematoporphyrin. Since the occurrence of hsematoporphyrin in the 

 urine in various diseases has been made very probable by several investi- 

 gators, such as NEUSSER, STOKVIS, MACMUNN, LE NOBEL, COPEMAN, and 

 others, 5 SALKOWSKI has positively shown the presence of this pigment 

 in the urine after sulfonal intoxication. It was first isolated in a pure 



1 See Maly's Jahresber., 18. 



2 For more details in regard to the preparation of the reagents and the performance 

 of the reaction see O. Schumm., Zeitschr. f. physiol. Chem., 50. 



3 Zeitschr. f. anal. Chem., 11. 



4 Zeitschr. f . physiol. Chem., 41. 



5 A very complete index of the literature on haematoporphyrin in the urine may be 

 found in R. Zoja, Su qualche pigmento di alcune urine, etc., in Arch. Ital. di. clin. 

 Med., 1893. 



