x SPECTRUM OF HEMOGLOBIN-COMPOUNDS 479 



oxy haemoglobin is that of Curtius-Hiifner. 1 Curtius recommended 

 salts of hydrazin, and Hiifner 2 then introduced hydrazin- hydrate, 

 because the only products of its decomposition are nitrogen and water : 



H 2 N - NH 2 . H 2 + 2 = N 2 + 3H 2 0. 



For a full account of the different reducing methods consult Gamgee's 

 account in Schafer's Textbook of Physiology, vol. i., p. 230 (1898). 



Subsequently Hiifner and v. Noorden 3 have devoted great care to 

 the visible spectrum, while Soret 4 and especially Gamgee 5 have studied 

 the absorption-bands in the violet and ultra-violet regions. 



A more complete account of the optical properties of the hemo- 

 globin derivatives than that given here will be found in the papers of 

 Formanek, 6 Ziemke and Miiller, 7 and Schulz. 8 The latter has studied 

 hfematoporphyrin very carefully. 



The theory and methods of spectro-photometry are fully explained 

 by Gamgee in Schafer's Textbook of Physiology, vol. i., p. 213 (1898). 



Fraunhof er's lines : 



A =X7606'1 

 B = X6S69'1 

 C =X6563-9 



D 2 = X5890-7 

 E = X5270'6 

 b =X5183'0 

 F = X4862'1 

 G = X4308'5 

 H =X3969'2 

 K = X3934-1 



v expressed in tenth-metres 

 = l + 10- ] metres. 



and then ammonia is added till the solution becomes alkaline. This mixture should be 

 always freshly prepared. 



1 Curtius, Journ. f. prakt. Chem. 39. 27 (1889). 



2 Hiifner, Bestimmung d. Sauerstoffcapacitat d. Blutfarbstoffs, p. 156. 



3 G. Hiifner, Journ. f. prakt. Chem. [2] 22. 362 (1880)'; C. v. Noorden, Zeitschr. 

 f.physiol. Cliem. 4. 9 (1879) ; in both papers will be found the theoretical exposition 

 of his methods; G. Hiifner, ibid. 1. 317 (1877); 1. 386 (1878); 3. 1 (1878); 8. 

 358 (1884) ; 10. 218 (1886) ; 12. 568 (1888) ; 13. 285 (1888). The final con- 

 clusions will be found in the following papers : G. Hiifner, Archiv fur (Anat. und] 

 Physiol. 1890, p. 1 ; 1894, pp. 130, 209 ; 1895, p. 213 ; 1901, Suppl. p. 187. 



4 Soret, ' Recherches sur 1'absorption des rayons ultra -violets par diverses sub- 

 stances,' Arch. d. sc. phys. et nat. Geneve, 1878, pp. 322, 359. 



5 Arthur Gamgee, Zeitschr. f. Biol. 34. 505 (1896). See also Schafer's Textbook of 

 Physiol. vol. i. (1898). 



6 J. Formanek, Zeitschr. f. analytische Chem. 40. 505 (1901) ; according to 

 Malys Jahresber. 31. 223. 



7 E. Ziemke and Franz Miiller, Arch. f. (Anat. u.) Physiol. 1901, Suppl. p. 177. 



8 Arthur Schulz, ibid. 1904, Suppl. p. 271. 



