Page:Popular Science Monthly Volume 76.djvu/189

Rh oxygen. On the other hand, recent work suggests that one of the means of increasing working power or temporarily, at least, delaying its loss, is by artificially supplying oxygen to the body. It has been known for some time that with the usual conditions under which we live, the main source of the energy of muscles and probably of other organs is carbohydrate material, glycogen or its near

relative, sugar. In the burning of carbohydrate in the tissues its potential energy becomes the actual energy of heat and muscle work. This fact would suggest the loss of carbohydrate as one of the factors in the oncoming of fatigue, especially in its later stages. Exact laboratory investigation, moreover, shows that if most of the carbohydrate be removed from an animal's body, he presents the symptoms of