Abstract
Non-nucleated mammalian erythrocytes do not respire even in the presence of sugar, but they do respire after addition of a small amount of methylene blue. It is shown in this paper that aqueous extracts of various organs, especially liver, act in the same way as methylene blue. The respiration of erythrocytes induced by an organ extract is not altered in the presence of carbon monoxide. The content of this respiratory supplement in extracts of organs varies according to the organ: liver and kidney show the best effect; muscle, brain, and blood serum the least. With hemolyzed erythrocytes no respiration can be induced either by methylene blue or by organ extracts.