HAEMOGLOBIN : ITS COMPOUNDS AND THE 
PRINCIPAL PRODUCTS OF ITS DECOMPOSITION. 
By Arthur Gamgee. 
Contexts. — Distribution in the Animal Kingdom, p. 186 — Relations to other Con- 
stituents of Red Corpuscles, p. 188 — Arterinl and Phlebin? p. 190 — Oxyhe- 
moglobin, p. 193 — Methods of obtaining, p. 194 — Composition of, p. 197 — 
Crystalline form, p. 203 — Action of Reagents on, p. 207 — Spectrum, p. 208 — 
Spectrophotometry, p. 213 — Photographic spectrum, p. 225— Haemoglobin, p. 
229 — Preparation of, p. 232 — Colour and Spectrum, p. 233 — Compounds with 
Gases, p. 237 — Derivatives and Products of Decomposition, p. 243. 
By the term haemoglobin 1 is designated the highly complex, iron-con- 
taining, crystalline colouring matter, which forms the most important 
constituent of the coloured corpuscles of the blood, 2 and in virtue of 
which they perform their function as the oxygen-carriers of the 
organism. This body possesses the remarkable property of linking 
to itself a molecule of oxygen, so as to form an easily dissociated 
compound, which is termed oxyhemoglobin, to distinguish it specifically 
from the colouring matter which has parted with its dissociable 
oxygen; for the latter some retain the name haemoglobin, though 
it is commonly, and by English writers usually, distinguished by 
the term reduced haemoglobin. 
Both oxyhemoglobin and reduced haemoglobin invariably (Hufner) 
exist side by side in varying proportions in the living blood; the 
former being must abundant in arterial, the latter in venous, blood. 
In the present chapter the term haemoglobin will be generally employed 
when speaking of the blood-colouring matter, without specific reference 
to its relation td oxygen; the term reduced hcemoglobin being invariably 
employed when reference is made to the colouring matter, deprived of 
its dissociable, or, as we may term it, in consideration of the part which 
it plays in the organism, its respiratory oxygen. 
Should we speak of "haemoglobin" or "the haemoglobins," of 
" oxyhemoglobin " or "the oxyhemoglobins ? " — In a subsequent 
section, it will be shown that the blood-colouring matter is by no 
means absolutely identical in all animals, but that it exhibits con- 
siderable variations in certain physical characters, and in chemical 
1 Hoppe-Seyler, to whom we owe a threat part of our knowledge of the hlood-colouring 
matter, first suggested this term. "Urn Yerwechselungen zu vermeiden nenne ich das 
Blutfarbstoff ' Htemoglobulin oder Haemoglobin, '" Vircliow's Archiv,. 1864, Bd. xxix. S. 
223. 
2 Haemoglobin constitutes about 40 "4 per cent, of the weight of the moist corpuscles, 
and about 95'5 per cent, of all the organic substances contained in them. 
