For example, the Eastern Coastal Party, sledging at fairly high temperatures over the sea-ice, noted that the full ration of hoosh produced at times a mild indigestion, they drank much liquid to satisfy an intense thirst and on returning to the Hut found their appetites inclined to tinned fruit and penguins' eggs. Bickerton's and Bage's parties, though working at a much higher altitude, had a similar experience. The former, for instance, could not at first drink the whole allowance of thick, rich cocoa without a slight nausea. The latter saved rations during the first two weeks of their journey, and only when they rose to greater heights and were in fine condition did they appreciate the ration to the full. Again, even when one becomes used to the ration, the sensation of full satisfaction does not last for more than an hour. The imagination reaches forward to the next meal, perhaps partly on account of the fact that marching is often monotonous and the scenery uninspiring. Still, even after a good evening hoosh, the subconscious self may assert itself in food-dreams. The reaction from even a short sledging trip, where food has been plentiful, is to eat a good deal, astonishing in amount to those who for the time being have lived at the Hut. It may appear that a serious case is being made against the polar sledging ration. On the whole, it was found to be excellent and the best that experience had been able to devise. Entering the polar zones, one must not be over-fastidious, but take it as a matter of course that there will be self-denial and deprivation of small luxuries. The energy exerted by man, and the requirements of tissue-building are derived from the organic compounds known as proteins,** fats and carbohydrates, though in a slight degree from other substances, most important of which are minute quantities of mineral matter. A calorie as used in dietetics is the amount of heat required to raise the temperature of one kilogramme of water at 0 degrees C. to 1 degree C. The heat-value of food-stuffs, stated in calories, can be quickly reckoned when chemical analyses stating their protein, fat and carbohydrate contents are available. It has been ascertained that one gramme of protein or carbohydrate yields 4.1 calories, whilst the same amount of fat produces 9.3 calories. Thus the value of fat-containing foods in a sledging ration is at once apparent. ** The proteins are complex nitrogenous compounds which are preeminent in fulfilling the two functions of a food: to form tissue and to produce work and heat. As examples may be quoted, myosin the chief protein of ordinary meat or muscle, ovalbumin one of the proteins of egg-white, casein belonging to milk and cheese, and gluten a protein-mixture in flour. Fats are organic non-nitrogenous substances obtained from both animal and vegetable sources, e.g. butter and olive oil.