Flat foot, cause of, 59-60; toeing-in and exercise of leg muscles as remedies for, 60; corrective exercises for, 223; consulting a specialist for, 223-224; means of detecting, 224-225; prevention of, 226. Fleas, as spreaders of disease, 74. Flesh eaters versus flesh abstainers, tests of, 197-199. Fletcher, Horace, interest in mastication revived by, 46; experiment with method of, of thorough mastication, 200-209. Flies, diseases carried by, 71; guarding against typhoid germs carried by, 73; methods of destroying, 73-74. Focal infection, as a cause of disease, 81; diseases traceable to, 82; caution necessary in accepting principle too literally, 83; physical examinations to detect, 292. Food, quantity of, 28; measurement of, by calories, 28; values of common foods, 29-30; the daily amount needed per person, 30; precautions regarding, in case of overweight, 32-33, 215-216; rules regarding, in case of underweight, 33, 219-220; diet in middle life, 33-34; diet in hot weather, 34; comparative amount needed by brain-workers, 34-35; eating when fatigued, 35; protein foods, 35-40; advantages of hard foods, 40-41; bulk a necessity in, 41-42, 148-150; objection to concentrated, 41; value of raw foods, 42; cooking necessary for some, 43; thorough mastication of, important, 44-47; enjoyment of, desirable, 46-47; choice of foods influenced by slow eating, 47; "good" and "bad" foods, 47-48; digestibility of so-called indigestible, 49; avoidance of fads as to, 50; consultation of physician regarding, 50; regulation of bowels by, 52; harmful preservatives and adulterants in, 65; comparative cost of, 129-131; drawbacks of civilization illustrated by, 148; soft and concentrated foods artificial, 148-150; the hurry habit and eating of, 150-151; misleading of appetites for, 151-152; tabular classification of common foods, 171; ideal proportion of the three elements in, 173; tabular list of values of, in daily diet, 175-183; relative energy value and cost of ready-to-serve foods, 184-190; minimal cost of, 190-194; calories consumed daily by different classes of workers, 195; experiments with mastication and instinctive eating, 200-209; references on, 209-211; negative value of alcohol as, 241-242. Fowl, a high-protein food, 38; special objections to too great an amount of, 39. France, consumption of alcohol in, 236; mortality statistics of, 286. Franklin, Benjamin, views of, concerning colds, 124. Fruit, to be eaten in middle life, 33; suitable for eating when fatigued, 35; cellulose supplied by fibrous, 41; vitamins supplied by, 42; acids supplied by, 43; among the best foods, 48; a laxative food, 52; value to teeth at end of a meal, 220. Fruit acids, cleansing the mouth with, 86.