IN the ruminant, the digestion of cellulose and other related carbohydrates is achieved through the conversion by the symbiotic flora of the paunch to simple fatty acids with the evolution of methane and carbon dioxide. If the fatty acids which are absorbed constitute the animal's main source of energy, it is possible that ruminants have a novel intermediary energy metabolism1 in which sugar may play a subordinate part. It is well known that the concentration of glucose in the blood of sheep and goats is normally much lower than that of animals which do not ruminate. Furthermore, relatively large quantities of insulin are necessary to reduce the blood sugar concentration of ruminants to the low levels which lead to hypoglycae mic distress2,3. Man and the usual experimental animals go into convulsions in such circumstances; sheep do not go into convulsions, they subside into an apathetic condition followed by coma.