The blood pigment of Arenicola

Abstract

The object which we had in view when we undertook the present research was to ascertain whether the pigment commonly alluded to as hæmoglobin in the worms was identical with that known by the same name in the vertebrates. Even in the mammalia there is some evidence that all hæmoglobin is not the same, many of the older observers held this to be the case; but since the discovery that the dissociation curve of hæmoglobin depends largely upon the conditions under which it is studied very little work has been done on the subject. It is known, for instance, that the blood of different persons differs slightly in its affinity of oxygen, under identical conditions, but such differences may be ascribed, rightly or wrongly, to variations in the intra-corpuscular atmosphere. More convincing evidence was put forward by C. G. Douglas, J. S. Haldane and J. B. S. Haldane (1) who showed that the blood of the mouse differed markedly from that of the human being. Their observations showed, among other things, that the curve which represents the reaction COHb+ O 2 ⇌ CO+HbO 2 in the mouse differed from that in man. This curve is little affected by the intra-corpuscular conditions of reaction and saline constitution, etc. Nevertheless one possibility was not excluded, namely, that the corpuscles of different animals should have a selective permeability for different gases.