x CO-HAEMOGLOBIN 499 



with its characteristic spectrum, as pointed out by Hoppe-Seyler ; 1 and 

 secondly, dilution of the suspected blood with water, as recommended 

 by Haldane. Vogel 2 was the first to use very dilute haemoglobin 

 solutions as a qualitative test for carbonic oxide in air. He shook a 

 small quantity of very dilute blood in a small bottle filled with the air, 

 and subsequently added ammonium sulphide. If the two bands of 

 oxyhaemoglobin were still present, then CO-haemoglobin had been 

 formed. By this means he detected 0*25 per cent of carbonic oxide. 

 Hempel, 3 by bubbling a large volume of air through a small quantity 

 of blood solution, detected up to 0'06 per cent of CO in air. Haldane's 4 

 method allows of detecting and estimating as little as "01 per cent of 

 carbonic oxide, or 0'2 per cent of coal-gas : 5 A clean and dry bottle of 

 100 to 200 cc. capacity has sucked through it 2 to 3 litres of the sus- 

 pected air the bottle is closed by a doubly perforated cork, soaked in 

 paraffin and fitting hermetically, and passing through the cork are two 

 pieces of glass tubing, each with a short piece of india-rubber tubing, 

 with a glass rod at the free end to act as a stopper. For the deter- 

 mination of the CO in the air, dilute about 5 cc. of a solution of 

 defibrinated ox-blood to 200 with water, and introduce the diluted 

 blood into the bottle, taking the following precautions : Remove one 

 of the glass stoppers from the india-rubber tubing, pinching the latter 

 all the time; now insert the pipette with the blood solution into 

 the india-rubber tubing and allow the blood to flow into the bottle 

 by removing the glass rod from the other piece of india-rubber 

 tubing, as hereby sufficient air is allowed to escape to diminish 

 the pressure inside the bottle. After the blood has flowed into 

 the bottle, replace both glass rods in the india-rubber tubing, and 

 shake the bottle fairly vigorously for twenty minutes. 6 A standard 

 solution of carmine is then used for titration. It is made by diluting 

 a stronger ammoniacal solution of carmine until the tint is such that 

 when the solution is mixed with an empirically found proportion of 

 the '5 per cent blood solution the tint of the mixture exactly resembles, 

 both as regards quality and intensity, a solution of similarly diluted 

 blood when saturated with carbonic oxide or coal-gas. The titration 

 is performed by daylight in two test-tubes of equal diameter, and 

 about 6 cc. of the standard carmine solution are required for 5 cc. of 



1 F. Hoppe-Seyler, Zentralbl.f. d. med. Wissensch. 1865, p. 52; Zeitschr. f. physiol. 

 Chem. 1. 121 (1877). 



2 Vogel, Ber. d. deutsch. chem. Ges. 10. 792 (1877) ; 11. 235 (1878). 



3 Hempel, Zeitsch. f. analyt. Chem. 18. 402 (1879). 



4 J. Haldane, Journ. of Physiol. 18. 464 (1895). 



5 The latter contains on an average 5 per cent of CO, according to Haldane. 



6 J. Haldane and J. Lorrain Smith, Journ. of Physiol. 22. 233 (1897). 



