The blood is coloured red by haemoglobin in blood corpuscles.
Haemoglobin is composed of a basic albumin and an acid substance haematin; it combines readily with oxygen, carbon dioxide and carbon monoxide to form loose compounds.
Haematogenous pigments are derived from the haemoglobin of the red blood corpuscles.
The ' haemoglobin may be transformed into haematoidin, a pigment that does not contain iron, or into a pigment which does contain iron, haemosiderin.
It is very poisonous, uniting with the haemoglobin of the blood to form carbonyl-haemoglobin.
It has been discovered in seaweed; in the blood of certain Cephalopoda and Ascidia as haemocyanin, a substance resembling the ferruginous haemoglobin, and of a species of Limulus; in straw, hay, eggs, cheese, meat, and other food-stuffs; in the liver and kidneys, and, in traces, in the blood of man and other animals (as an entirely adventitious constituent, however); it has also been shown by A.
Haemoglobin is extracted from the blood of an ox and may be administered in bolus form.
Iron being a constituent part of the blood itself, there is a direct indication for the physician to prescribe it when the amount of haemoglobin in the blood is lowered or the red corpuscles are diminished.
The first is based on the fact that the iron in the haemoglobin of the blood must be derived from the food, therefore iron medicinally administered is absorbed.
In certain forms of anaemia it increases the number of the red corpuscles and also their haemoglobin content.
At the same time the non-striped muscles slightly lose their tonicity, and when very large doses are given the haemoglobin of the blood becomes converted into the chocolate-coloured methaemoglobin.
It enters into combination with haemoglobin, forming a bright scarlet compound and interfering with respiration.
The haemoglobin would, by its pre-eminent properties of fixing oxygen, serve to furnish the nerve system, which more than any other requires a constant supply, with the necessary oxygen.
(2) Haemoglobin and allied substances.
An important nucleo-proteid is haemoglobulin or haemoglobin, the colouring matter of the red blood corpuscles of vertebrates; a related substance, haemocyanin, in which the iron of haemoglobin is replaced by copper, occurs in the blood of cephalopods and crayfish.
By a dilute acid haemoglobin is decomposed into globin, and " haematin," a ferri-pyrrol derivative of the probable formula C34H34N4FeOs; under certain conditions the iron-free " haematoporphyrin " is obtained.
Haematinics are drugs which increase the amount of haemoglobin in the blood.
Lxiii.; On the Distribution of Assimilated Iron Cornpotrnds other than Haemoglobin and Haematins, in Animal and Vegetable Cells, Quart.
The plasma is coloured red by haemoglobin: it is sometimes (in Sabella and a few other Polychaeta) green, which tint is due to another respiratory pigment.