Note 6 — VASCULAR SYSTEM WITH RED BLOOD.

It may be remarked, that this work was published at a time when the theory of the oxygenation of the blood was universally considered as explaining in a satisfactory manner the change that is effected in the colour of the blood by the lungs. The experiments of Allen, Pepys, and others, and the Treatises of Ellis, have proved to the satisfaction of most physiologists of the present day, that this change in the colour is not owing to the absorption of oxygen by the blood, but to the extrication of carbon from it. Tr.