Musical Terms, from Italian, xv, 161 Musk, source of, xii, 322; spread of odor of, iv, 131, xi, 80 Musk Deer, xii, 322 Muskox, xii, 328; in glacial period, xiv, 376 Muskrats, xii, 289, 290 Mussels, xii, 58-67; in lakes, xiv, 211-12 Mustangs, xii, 307 Mustard, effects on stomach, ix, 243-4; origin, xiii, 265 Mustard Family, xiii, 197 Mustard Gas, viii, 263, 264, x, 187 Mustard Plant, fruit, xiii, 57 (fig.); leaf, 38 Mustard Seed, xiii, 60 Mutants, Mutation, ix, 342-3, xiii, 333-4, xv, 23-4, xvi, 155 Mutilations, of body, xv, 257-60; regeneration of, xii, 170 Muybridge, Edward, v, 330 Myer, Gen. Albert J., i, 217, 220 Myopia, ix, 112 Myotomes, xi, 34, 35 Myrtles, antiquity, xiii, 324-5 Mythology, beginnings of, xv, 357-8 Myxedema, x, 272, 349-50, 351 Nacre, xii, 59 Naias, fertilization, xiii, 151-2 Naids (Naidae) xii, 53-5, 65-6 Nails, former making of, by smiths, iv, 49 Nails (body) cells of, ix, 13 Names, and perceptions, xi, 160-1 Naphthalene, viii, 51, 240, 253 Napier, John, logarithm invention, xvi, 104 Naples, Bay of, crustal movements about, iii, 80-1 Napoleon, dissolution of Salerno University, x, 36; Egyptian campaign, mirage, i, 172; indigestion before Waterloo, ix, 238; Italian campaign, xiv, 244; military road over Alps, 241; Russian campaign, i, 306-7; vaccination order, x, 102-3 Napoleon III, brain weight, xv, 39 Narragansett Bay, oysters of, xii, 61; scallop fisheries, 65 Narrow-mindedness, muscular causes, xi, 372; of grinds and thrill-hunters, 376 Narwhales, xii, 297 Nassa, xii, 70 Nassir Eddin, ii, 39 Nasturtium, leaves, xiii, 33 (fig.); roots, 16 (fig.); water-dripping by, 108 Natal, forests and grasslands, xiii, 375, 376; hailstorm, i, 119 Naticas (mollusks), xii, 73 Native Shrubs, advantages, xiii, 273; planting table, 274-89 Natural Bridges, iii, 127 (fig.), 128 Natural Gas, iii, 354; composition, viii, 208; exhaustion of supply, v, 173; found with petroleum, iii, 350-3, 354, 355; low luminosity, viii, 60; origin and occurrence, iii, 354-5; waste, 355 Natural History School, of medicine, x, 113 Naturalism, development, xvi, 111, 115 Natural Sciences, xvi, 139-48 Natural Selection, x, 135, 136, xv, 23, 24, xvi, 150-1, 152; disease and, xv, 48; in man, xv, 47-8; working of, xii, 293, xiii, 334-5, 346, xv, 24-5 (see also Struggle for Existence, Survival of Fittest)