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.
The carbohydrates are compounds of carbon with hydrogen and oxygen in a certain proportion, e.g. cane-sugar and starch.
Mineral matters are inorganic, being chlorides, carbonates or phosphates of calcium, sodium and potassium.
Theoretically, any of the three classes of foods mentioned might be thought to supply adequate energy, if taken in sufficient amount. Practically, however, protein and carbohydrate are essential, and it is better to have a mixture of all three. So, in concentrating foods for sledging, the largest possible proportion of fat, compatible with other considerations, is included.
Ordinarily, a normal man consumes some four or five pounds weight of solid food per diem, of which 50 per cent., it is rather surprising to learn, is water. When sledging, one has the satisfaction of knowing that all but the smallest quantity of the food dragged is solid nutriment. The water is added when the meals are cooked. It is just in this artificial addition that the sledging ration is not perfect, though as a synthesis it satisfies the demands of dietetics. Food containing water, as cooked meat oozing with its own gravy is a more palatable thing than dried meat-powder to which boiling water has been added. In the same way, a dry, hard biscuit plus liquid is a different thing from a spongy loaf of yeast bread with its high percentage of water. One must reckon with the psychic factor in eating. When sledging, one does not look for food well served as long as the food is hot, nourishing and filling. So the usage of weeks and a wolfish appetite make hoosh a most delicious preparation; but when the days of an enforced ration are over, the desire for appetizing well-served food reasserts itself. The body refuses to be treated merely as an engine.