Observations and experiments on the colour of blood / [William Charles Wells].

  • Wells, William Charles, 1757-1817
Date:
[1797]
Catalogue details

Licence: Public Domain Mark

Credit: Observations and experiments on the colour of blood / [William Charles Wells]. Source: Wellcome Collection.

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    thought, that the mild volatile alkali, which has been supposed by chemists to superabound with phlogiston, can yet attract it from blood. It appears to me, however, unnecessary to bring any further arguments of this kind against the opinion of Dr. Priestley, since the following experiments will, I expect, be thought sufficient to shew, in opposition to what is taken for granted by him in the whole of his inquiry, that the alteration induced upon the colour of blood, both by common air and the neutral salts, is altogether independent of any change effected by them upon its colouring matter. I infused a piece of black crassamentum of blood in dis¬ tilled water, and immediately after covered the containing vessel closely, to prevent the access of air. Having obtained by this means a transparent solution of the red matter of blood, nearly free from serum and coagulable lymph, I exposed a quantity of it to the open air, in a shallow vessel, and poured an equal quantity into a small phial, which was then well closed. When the first portion of the solution had been ex¬ posed to the air for several hours, I* decanted it into a phial, of the same size and shape as that which contained the second portion, and having added to it as much distilled water as was sufficient to compensate the loss it had suffered by evapo¬ ration, I now compared the two together, and found them to be exactly of the same colour, with regard both to kind and degree. I afterwards poured two other equal quantities of the red solution into two phials of the same size and shape. To one I added a little of a solution of nitre in water, and to the other as much distilled water. Upon comparing the two mix¬ tures together, I found that they also possessed precisely the same colour. Lastly, I cut a quantity of dark crassamentum