Aneroid Barometer, i, 71, 72, 366, iv, 123-4, 381 Anesthetics, discovery and use in surgery, x, 123-5, 148, xvi, 180, 185; effect on impulses, xi, 20; Hindu use of, x, 13; medieval, 41 Aneurisms, x, 28 note; formation and rupture of, 336; treatment of, 28, 91-2 Angel Fish, xii, 164 Anger, xi, 139, 141; basic causes of, ix, 153, 166; expression of, by monkeys, xv, 64; in various sentiments, xi, 146, 148, 149, 150; pain and, 120; physical accompaniments of, ix, 240-1; self-forgetfulness in, xi, 134 Angiosperms, xiii, 175-9; alternation of generations in, xvi, 166; first appearance and spread, iii, 256-7, xiii, 317-18 Anglers, (fish) eyes of, xii, 138; "lure" of, 133 Angleworms, xii, 51-3; power of distinguishing light, ix, 105 Anglo-Saxon Language, xv, 156-7 Anglo-Saxons, in Nordic group, xvi, 48; use of tea, xiii, 229 Angular Diameters of Stars, ii, 150-1; measurement of, 322-3 Anhydride, defined, viii, 374 Aniline, viii, 52, 237 Aniline Dyes, xvi, 163; fluorescence of, iv, 379 Animalculæ, (see Unicellular Animals) Animal Electricity, vi, 16, 17, 19, 23, 64 (see also Electric Fishes) Animal Fats, viii, 246 (see Fats) Animal Kingdom, classification, iii, 259-60, xii, 25-9; how distinguished, viii, 349, xii, 14, 15, xiii, 13, 14; relations to vegetable, viii, 334 Animal Protein, ix, 279, 280 (see also Proteins) Animals, xii, 270; activities of, ix, 20-1; adaptation to environment, v, 16-18, 24, xvi, 152; admiration unfelt by, xi, 146; æsthetic emotions, xvi, 145-6; anaphylaxis in, x, 212, 213, 214; appendix uses in, xv, 56; appetite in, ix, 88; arctic, in mountains, xiv, 376-7; artificial heat use by, ix, 308, xv, 229-30; body heat regulation in, ix, 307, 308, 311; brain in, xv, 62-3; cannibalism in, ix, 280-1; care of skin and coverings by, x, 310; care of young, xv, 275-6; carnivorous, xii, 332-65; cell structure, 25; chemistry of body and nutrition, viii, 348-70; chromosomes in different species, ix, 46; classification, xii, 25-9; climatic influences, xvi, 141; climatic limitations, xiv, 363-64; cold-blooded (see Cold-blooded Animals); communication means, xv, 140-1; courtship of, 274-5; differences of protoplasm in, ix, 278-9; direction perception by, 117; differences of complexity in, 48-50; diseases of, x, 206; distribution facilitated by land arrangement, xiv, 21; domestication of, xv, 197-8; ear movements in, ix, 82, 117; educability of, xv, 66; embryological development, 54-5; evolution, Anaximander on, xvi, 78-9; experience, profiting by, ix, 139, 152, xv, 66; expressions of emotions by, 63-5; face and brain case in, 43; fear in various, xi, 136; fear and anger effects, ix, 166; flesh of, as food, 24, 284-6, xv, 333-4;