DE. A. GAMGrEE ON THE ACTION OE NITEITES ON BLOOD. 
591 
tion spectrum almost identical with that of the O-compound 1 . It may be obtained 
in well-defined crystals which are isomorphous with those of the O-compound 2 . 
7. Similarly the CO-compound may be decomposed by nitric oxide, one volume of 
CO being apparently replaced by one volume of N 2 0 2 . The body thus formed may 
be obtained in crystals isomorphous with those of the O- and the CO-compounds. Like 
the latter it is unacted upon by reducing solutions 3 . 
8. Hydrocyanic acid when added to blood appears to combine with the colouring- 
matter ; the nature of the compound formed has not, however, been ascertained. It 
may, however, be obtained in crystals identical with those of the O- and CO-compound. 
Its spectrum is identical with the former and, like it, is capable of reduction 4 . 
9. When heated, or when treated with strong acids and alkalies, haemoglobin furnishes 
amongst other products of decomposition, an insoluble body called hsematin 5 , which was 
until recently supposed to be the colouring-matter of blood 6 . This body possesses no 
power of combining with oxygen. The absorption-coefficient of oxygen for a solution 
of haematin is nearly the same as for water 7 . 
Note. — The author has purposely avoided entering upon the description of the inte- 
resting physical properties and chemical reactions and relations of haematin, as these do 
not immediately concern the object of this memoir. 
On the Action of Nitrites on Blood. 
No one has hitherto investigated the action which the nitrites exert upon the blood 
and upon its colouring-matter. Two of the oxides of nitrogen have been studied in their 
relation to blood by Dr. Ludimar Hermann, viz. laughing-gas 8 and nitric oxide 9 . With 
regard to the first of these, it has been shown that it acts upon blood and haemoglobin 
very much as hydrogen, carbonic acid, and nitrogen, whilst in reference to the second, 
Hermann has shown that it actually combines with the colouring-matter. 
My attention was directed to the peculiar action of nitrites upon the blood-colouring- 
matter by observing that the blood of mice poisoned by exposure to an atmosphere im- 
pregnated with the vapour of nitrite of amyl presented a chocolate-colour. I was thus 
1 Hoppe-Seyler, Medicinisch-chemische U nter su chun gen, zweites Heft, p. 203. 
2 Hoppe-Seylek, Med.-chem. Unters. p. 201. 
3 Dr. Ludimar Hermann, “ Ueber die wirkungen des Stickstoffoxydgas auf das Blut,” Muller’s Archiv, 1865, 
pp. 469-481. 
4 Hoppe-Seylee, Med.-chem. Untersuchungen, 11 Heft, p. 206. Preyeb, Yirchow’s Archiv, 1867, Sept, 
p. 125. 
5 Hoppe, Yirchow’s Archiv, Bd. NXIII. p. 446. Stokes, op. at. p. 355 et seq. 
6 The reader who wishes to become acquainted with the different methods employed formerly for separating 
haematin are referred to Gorup-Besanez, Lehrbuch der Phys. Chemie, Braunschweig, 1862, p. 168 et seq. 
Berzelius clearly distinguished the difference between the unaltered colouring-matter and the coagulated 
colouring-matter. — Traite de Chimie, par J. T. Berzelius, Paris, 1833. t. vii. pp. 48-65. 
7 Lothar Meyer, De sanguine oxydo carbonico infecto, pp. 9-12. 
8 “ Ueber die physiologischen wirkungen des Stickstoffoxydulgases,” Muller’s Archiv, 1864, p. 521. 
9 “ Ueber die wirkungen des Stickstoffoxydgas auf das Blut,” Muller’s Archiv, 1865, p. 469. 
MDCCCLXVIII. 4 M 
