Nitrogenous metabolism, theory of Folin, 144 theory of Pflüger, 138 theory of Voit, 134 Normal diets, 155 Nutrition, factors in, 16, 17 influence of chemical character of proteid on, 256 inorganic salts, as aids in, 2 physiological economy in, 264 purpose of, 2 Nutritive balance, as affected by various factors, 117, 118 Nuclease, 71 Nucleoproteid, character of, 3 cleavage products of, 71 O Obesity, relation to food consumption, 270 Old age, metabolism in, 296 Osborne and Clapp, on chemistry of proteids of wheat kernel, 258 Osmosis, as factor in absorption, 41 Overeating, evil effects of, 270 Overfeeding, in laying on of fat, 98, 99 Oxidase, xanthin, 73 Oxidases, 64 Oxidation, in metabolism, 60 nature of, in the body, 60 older views regarding, 52 relation to enzymes, 75 site of, in the body, 62 value of respiratory quotient in determination of substances undergoing, 125 views of Lavoisier on, 56 views of Liebig on, 57, 120 Oxidative cleavage, 61 Oxygen, in katabolism, 62 relation to decompositions in the body, 61 relation to proteid decomposition, 59 Oxygen consumption, in climbing, 116 in relation to work, 123 in standing at rest, 116 in walking, 116 P Pancreatic digestion, of proteids, 34 products of, 34, 67 products of, of starch, 37 Pancreatic juice, composition of, 32 condition of trypsin in, 33 enzymes in, 32 secretion of, 31, 32 sodium carbonate in, 32 Paths of absorption, 44 Pawlow, on adaptation of saliva, 18 Pepsin, in gastric juice, 25, 26 Peptones, 67 absorption of, 41 cleavage by erepsin, 34 effects when injected into blood, 41 formed in gastric digestion, 26 Pflüger, E., theory of proteid metabolism, 138 views on muscle work, 123 Phenol, 37 Phloridzin diabetes, 130 Phosphorus, excretion of, in relation to work, 123 Photograph, of athlete, 190 of Fritz, 199 Photographs, of dogs, 248 of soldiers, 193 Physical endurance, _see_ Endurance Physiological economy in nutrition, 264 Plastic foodstuffs, 58 Poisons, relation of body resistance to, on low proteid diet, 226 Polypeptid, 35 Portal vein, absorption of food products by, 45 Processes of metabolism, 51 Products, of cleavage of wheat kernel proteids, 259 of gastric digestion, 26 of pancreatic digestion, 37, 67 of proteid cleavage, 70 of putrefaction in intestine, 38 of salivary digestion, 21 Products of digestion, absorption of, 44 Professional men, fuel value of food on low proteid diet, 178, 180, 185 nitrogen equilibrium of, on low proteid diet, 176, 177, 181 true proteid requirement of, 174 Progeny, influence of meat diet on, in rats, 240 Prosperity, relation to food consumption, 160