Dairy products, table of food values of, 181. Dampness of air, exaggeration of evils of, 19. Dancing, question of hygienic value of, 99-100; an obstacle to efficiency when overdone, 100. Death rate, lowering of, by public hygiene, 158-159; statistics of overweight, 213; influence of alcohol on, 228-235, 262; influence of tobacco on, 262; fall of, in younger age groups, and rise at older age periods, in United States, 281; cause of increase in, 282; charts showing trend of, 283-285; comparison of, among different nations, 286-291. Defectives, segregation and sterilization of, 321-322, 323. Degenerative tendencies among nations, comparison of, 286-292. Delusions, certain popular, concerning diseases, 123-125. Denmark, mortality statistics of, 291. Dental clinic, beneficial results of, 88. Dental decay, process of, 79. Dental floss, use of, 85. Desires, controlling intensity of one's, 117-118. Desk, posture in sitting at a, 61. Despondency, sometimes caused by a slouching posture, 57. Desserts, table of food values of, 179. Diabetes, in relation to focal infection, 82; aggravations of, 123. Discontent, physical sources of, 105-106. Diseases, caused by absence of vitamins from food, 42; carried by mosquitoes and flies, 71; caused by focal infection, 82; preventability of, 135-136; relation between consumption of alcohol and increase in degenerative, 235-236; effect of alcohol on bodily resistance to, 239-240; caused by smoking, 263-264; signs of increase of the degenerative, 281-285. Disinfection of foods, 43. Drafts, unreasonable prejudice against, 8; exaggeration of idea that colds are derived from, 8-9; popular delusions concerning, 123-124; exposure to, a means of skin training, 274; avoidance of, after catching cold, 277. Drugs, avoidance of, for constipation, 53; habit-forming, as poisons, 65; alcohol to be classed among, 242. Dryness of air, 11, 19; question of ill effects from extreme, 12. Duodenum, ulcer of, caused by focal infection, 82. Dust, air vitiation from, 13; methods of removing, 13; bacteria carried by, 13-14. Dusty trades, morbidity and mortality rates in, 13. Dyspepsia among smokers, 264. Eating, before retiring, 103; in case of colds, 279-280. Eating habits. _See_ Food. Education on inheritability of traits, need of, 323. Eggs, food value of, 29, 38, 183; for underweight, 220. Emetin, use of, in treating pyorrhea, 85-86. Emotions, exercise of the, 97. Endurance, experiments to determine effect of different diets on, 197-199; experiments with mastication, and instinctive eating, 200-209. Enema, use of, for constipation, 53. England and Wales, trend of death rate in, 283-284; mortality statistics of, 287; expectation of life in, 290.