1. Iodoacetate inhibits aerobic as well as anaerobic activity of the isolated rabbit's auricle. Under
aerobic conditions, a rabbit's auricle inhibited by
I.A.A. can be revived by lactate, pyruvate,phosphoglycerate and propionate. Glucose, glycerophosphate, caproate,butyrate,valer ate,malate,succinate,fumarate,
and amino-acids, including glycine, alánine and glutamie acid have no revival effect.
2. Fluoride has no action upon aerobic activity
of the frog's heart and the isolated rabbit's auricle
but inhibits their anaerobic activity. It is suggested
that fluoride, while it inhibits glycolysis, has no
action upon the oxidation of non -carbohydrate material.