A Theory of Tracheal Respiration in Insects

IT has been shown by Krogh (Arch. f. Ges. Physiol., vol. 179; 1920) that the laws of diffusion of gases will explain the supply to the tissues of insects of those quantities of oxygen which they actually consume. This theory is satisfactory so far as it goes, but it makes no provision for such increased demands for oxygen as must arise locally in active tissues. It is the purpose of this letter to outline a theory, complementary to that of Krogh, which will satisfy these requirements, and to indicate the experimental evidence by which this theory is supported.