CARBONIC OXIDE-HEMOGLOBIN. 31 



one ia the broader, and extends more into the red. If ammonium sulphide be 

 added to the methaemoglobin solution, reduced Hb is formed (Jiiderholm). Methae- 

 raoglobin is produced in old brown blood-stains, in the crusts of bloody wounds, in 

 blood cysts farther by the addition of minute traces of acid to blood, or by 

 heating blood with a trace of alkali. Sorby and Jaderholm regard it as a per- 

 oxidised haemoglobin, but this view is opposed by Hoppe-Seyler. It may also 

 be prepared by acting upon blood with potassic chlorate and nitrate, or nitrate of 

 amyl, which gives to blood a chocolate-brown colour (Saarbach, Gamgee). 



16. Carbonic Oxide-Haemoglobin. 



(3.) CO-Hsemoglobin is a more stable chemical compound than the 

 foregoing, and is produced at once when carbonic oxide is brought into 

 contact with pure Hb or 2 Hb (Cl. Bernard, 1857). It has an 

 intensely florid or cherry-red colour, and gives two absorption-bands, 

 very like those of 2 Hb, but they are slightly closer together and lie 

 more towards the violet (Fig. 11, 3). Reducing substances (which act 

 upon Hb0 ) do not affect these bands, i.e., they cannot convert the CO 

 compound into reduced Hb. Another good test to distinguish it from 

 Hb0 2 is the soda test. If a 10 per cent, solution of caustic soda be 

 added to a solution of CO-Hb, and heated, it gives a cinnabar-red colour; 

 while, with an Hb0 2 solution, it gives a dark-brown, greenish, greasy 

 mass (Hoppe-Seyler). Oxidising substances [solutions of potassic 

 permanganate (O025 per cent.), potassic chlorate (5 per cent.), and 

 dilute chlorine solution] make solutions of CO-Hb, cherry-red in 

 colour, while they turn solutions of HbO., pale yellow. After this 

 treatment both solutions show the absorption-bands of methaemoglobin. 

 If ammonium sulphide be added, Hb0 2 and CO-Hb are re-formed. 



On account of its stability CO-Hb resists external influences and even putre- 

 faction for a long time (Hoppe-Seyler), and the two bands of the spectrum may be 

 visible after many months. Landois obtained the soda test and spectroscopic 

 bands in the blood of a woman poisoned 18 months previously by CO, and after 

 great putrefaction of the body had taken place. 



If CO is breathed by man, or if air containing it be inspired, it 

 gradually displaces the 0, volume for volume, out of the Hb (L. Meyer), 

 and death soon occurs; 1,000 ccm inspired at once will kill a man. 

 A very small quantity in the air (^^"T^V o) suffices, in a relatively 

 short time, to form a large quantity of CO-Hb (Grehant). As 

 continued contact with other gases (such as the passing of through 

 it for a very long time) gradually separates the CO from the Hb 

 (with the formation of 2 Hb Donders), it happens that, in very partial 

 poisoning with CO, the blood gradually gets rid of the latter. A 

 high degree of poisoning necessitates the transfusion of blood (p. 61). 



[Gamgee and Zuntz also find that although the CO-Hb compound is very stable, 

 yet it may be reduced by passing air or neutral gases through, it for a lengthened 

 period ; it is also reduced when blood is boiled in the mercurial pump. ] 



