gh the mouth, 78-83;
in colds, 272.

Infectious diseases, power of resistance to, weakened by alcohol, 68;
results regarding, from teeth hygiene, 88.

Insect-borne diseases, 71.

Insomnia, remedial measures for, 102-103;
often caused by excessive smoking, 264.

Instinctive eating, experiments with, 200-209.

Intestinal intoxication, distinguished from autointoxication, 81-82.

Intestinal poisoning, from insufficient mastication, 45.

Introspection, one of the curses of idleness, 91.

Iron, in vegetable foods, 40.

Italy, mortality statistics of, 286.

James, William, on enjoyment of life, 5;
on religion of healthy-mindedness, 114.

Jews, effects of indoor living withstood by, 147.

Kidney, among the worst foods, 48.

Kidneys, death rates from diseases of, 284, 285.

Kipling, Rudyard, on concentrated foods, 41-42.

Labor, modern ideals concerning, 3-4;
turned from drudgery into play by proper development of health
ideals, 5-6;
division of, an evil of civilization, 152.
_See_ Work.

Lamb, food value of, 29, 178.

Laxative drugs, avoidance of, 53.

Laxative foods, 52.

Leg-lifting exercise for faulty posture, 222.

Lettuce, cellulose in, 41;
vitamins supplied by, 42;
food value of, 175.

Lice, diseases carried by, 74-75.

Life, no principle which limits, 142-143;
shortening of, by unhygienic modes of living, 155.

Life Extension Institute, purpose of, 1.

Lighting, electric preferable to gas, 13.

Lime, deficiency of flesh foods in, 39.

Linen, use of, in clothing, 17.

Literature, avoidance of morbid, 99.

Liver, excess of acids produced by eating, 39;
among the worst foods, 48.

Liver diseases, death rate from, 285.

London, expectation of life in, 289.

Lusk, Graham, quoted on minimal cost of food, 190-194;
experiments by, to ascertain basal metabolism of body, 196.

Malaria, not caused by night air, 22;
carried by mosquitoes, 71.

Marriage, effect of health on opportunities for, 2;
exercising wisdom of choice in, 165-166;
enactment of wise laws of, 167;
science of eugenics and, 293-323.

Mastication, required by hard foods, 41;
value of thorough, and evils of insufficient, 44-47;
a desirable means of tooth and gum hygiene, 84;
and mental attitude, 110;
experiment to test effects of, on endurance and stren