When food is chiefly liquid, (soup, for example,) the fluid part is rapidly absorbed. The solid parts remain, to be acted on by the gastric juice. In the case of St. Martin,[F] in fifty minutes after taking soup, the fluids were absorbed, and the remainder was even thicker than is usual after eating solid food. This is the reason why soups are deemed bad for weak stomachs; as this residuum is more difficult of digestion than ordinary food. In recovering from sickness, beef-tea and broths are good, because the system then demands fluids to supply its loss of blood. Highly-concentrated food, having much nourishment in a small bulk, is not favorable to digestion, because it cannot be properly acted on by the muscular contractions of the stomach, and is not so minutely divided, as to enable the gastric juice to act properly. This is the reason, why a certain _bulk_ of food is needful to good digestion; and why those people, who live on whale oil, and other highly-nourishing food, in cold climates, mix vegetables and even sawdust with it, to make it more acceptable and digestible. So, in civilized lands, bread, potatoes, and vegetables, are mixed with more highly-concentrated nourishment. This explains why coarse bread, of unbolted wheat, so often proves beneficial. Where, from inactive habits, or other causes, the bowels become constipated and sluggish, this kind of food proves the appropriate remedy. One fact on this subject is worthy of notice. Under the administration of William Pitt, for two years or more, there was such a scarcity of wheat, that, to make it hold out longer, Parliament passed a law, that the army should have all their bread made of unbolted flour. The result was, that the health of the soldiers improved so much, as to be a subject of surprise to themselves, the officers, and the physicians. These last came out publicly, and declared, that the soldiers never before were so robust and healthy; and that disease had nearly disappeared from the army. The civic physicians joined and pronounced it the healthiest bread; and, for a time, schools, families, and public institutions, used it almost exclusively. Even the nobility, convinced by these facts, adopted it for their common diet; and the fashion continued a long time after the scarcity ceased, until more luxurious habits resumed their sway. For this reason, also, soups, gellies, and arrow-root, should have bread or crackers mixed with them. We thus see why children should not have cakes and candies allowed them between meals. These are highly-concentrated nourishments, and should be eaten with more bulky and less nourishing substances. The most indigestible of all kinds of food, are fatty and oily substances; especially if heated. It is on this account, that pie-crust, and articles boiled and fried in fat or butter, are deemed not so healthful as other food.