The Role of Certain Metallic Ions as Oxidation

I t has long been known tha t metals in some way are ve ry closely connected with the processes of respiration and oxidation in bo th plants and animals, and the mode of their action has been the subject of a great deal of research and discussion. The most impor tan t of these metals is undoubted ly iron, and the recent work of Warburg (1925) and Meyerhof (1924) has gone far toward elucidating its mode of action. 1 I ron as an oxygen carder is present in the hemoglobin of the blood of mammals and has been the subject of much invest igation. I t is not within the province of this paper, however, to discuss this aspect of the mat ter , t r ea tmen t of which m a y be found in text-books of general physiology. Next to iron, in occurrence and in importance, is copper, a l though the la t te r has not received the careful and a t ten t ive research which has been bestowed on the former3