Abstract
In the following propositions the leading facts which have been ascertained by previous observers with regard to the colouring-matter of the blood and its relation to gases have been condensed. 1. The colouring-matter of blood, to which the names of Cruorine 2 or Hæmoglobin 3 have been given, occurs in solution in the blood-corpuscles, but may by suitable treatment be obtained from them in the form of crystals, which when seen individually are of a yellow, and when seen collectively are of a reddish colour. Their solution possesses the property of absorbing light so as to yield a remarkable spectrum characterized by two very well-defined absorption-bands situated in the yellow and green portions of the spectrum, and by the cutting off of the greater part of the more refrangible rays 4 .