Animal Physiology

Our knowledge of the action of caffeine on the respiratory arrangement has resulted mainly from studies on the effect of the drug on the rate and round of respiration, alveoli and total ventilation of the lungs, and on the volume of gas exchanged among the organism and its environment. Edsall and Means (1), Grabfield and Means (2), Higgins and Means (3), Lohr (4), Schmidt and Harer (5), Smith (6), Fsungming (7).There seems to be a general agreement among these investi- gators that caffeine stimulates the respiratory center resulting in an growth in the rate of respiration and an increase in the oxygen utilisation and carbon dioxide elimination. This in- crease in the gaseous exchange may non be entirely due to stimulation of the respiratory center, but to nearly other factor such as an increase in the main(a) metabolism.Owing to the fact that practically all of the previous experiments were conducted on mammals, which have the highest authentic nervous system of any group of animals, and in order to stick out more light on the fundamental effect of the drug on physiological processes, it was thought desirable to study the effect of caffeine on the oxygen consumption of lower organisms.For this purpose it was found advantageous to exercise young individuals (3 to 4 inches in length) of a fresh water fish, Erimyson sucetta oblongus, Mitchell (identifled by Dr. T. H. Langlois, University Museum, University of Michigan) and bull frog tadpoles, Rana catesbiana. These ani- mals remain rather quiet when not disturbed, thus the error in 1 Contribution from Battle creek College. 5960 FLOYD J. BRINLEY oxygen consumption due to bodily activity of the animals is reduced to a minimum but not completely eliminated. M