Chloroform, viii, 52, 212; as anesthetic, x, 125 Chlorophyll, ix, 26, 27, xii, 11-12, 14, xiii, 79-80, 81, 84; absent in saprophytes, 99, 100; action in plants, viii, 335 Chocolate, calories in, ix, 299; history and production, xiii, 233-5 Choice, power and importance, xi, 260-3, 265-7; power of, in muscular responses, ix, 95, 121, 140 Choke Coils, vii, 17, 50 Cholera, discovery of germ of, x, 149, xvi, 184; former ideas of, x, 286; from water pollution, viii, 318; germ of, x, 195; immunity to, 207; inoculation against, 208; racial susceptibility to, xv, 50, 51 Choleric Temperament, xi, 153 Cholesterin, ix, 275 Chordates, xii, 127-9; coelom in, 27 Chords, major and minor, xi, 106-8 Chorea, epidemic of, in Europe, x, 60; rheumatism and, 224; Sydenham on, 74 Christianity, Locke's "rational," xvi, 115; Roman and medieval development, 99-100 Christian Science, attitude toward pain, xi, 116; source of power, 306 Christmas Trees, electric lighting, vii, 342 Chromatic Aberration, ii, 99-100 Chromatin, ix, 41, 42, 44-7, 328 Chrome Yellow, viii, 162 Chromium, viii, 154; affinity strength, 128; alloys of, 273; atomic weight and symbol, 383; extraction from ores, 271; specific gravity, 384; test for, 287, 288-9; use and occurrence, xiv, 238 Chromophor Group, viii, 258, 259 Chromosomes, ix, 46; arrangement in pairs, 329, 330; heredity controlled by, 328-41, x, 232-3; human varieties, 233; likeness in all cells, ix, 329; number of, 46, 329, 339; origin of energies, xvi, 145; sex, ix, 339, x, 234, xvi, 156; splitting of, in cell division, ix, 45 (fig.), 46-7, 332, 333 Chronic Diseases, wasting process of, x, 214 Chronometers, v, 65-7; regulation to temperature changes, iv, 148 Chrysolite, iii, 334 Church, Prof. J. E., i, 118 Chyme, x, 325, 326 Cicadas, xii, 112 Cider, making of, viii, 249; turning to vinegar, 218 Cigarette-smoking, dust particles from, i, 62 Cilia, of bronchial tubes, x, 202; of simple animals, ix, 73-4 Cinchona, use of, in medicine, x, 154-5, xvi, 109 Cinchona Plantations, xiii, 251-2 Cincinnati, early growth, xiv, 219; water supplies, viii, 318, 322 Cinder Cone, eruption, iii, 226 Cinder Cones, xiv, 100, 102 Cinematograph, in astronomy, i, 162, ii, 212 Cinnabar, iii, 327, 370 Cinnamon, xiii. 263-5 Circles, appearance of circumscribed, xi, 186; divisions invented by Ptolemy, xvi, 94; regarded as perfect curves, ii, 34, 49 Circuit Breakers, vi, 101-3, vii, 36, 37-48 Circuits, Electrical, kinds defined, vii, 364; overloading of, vi, 9, 72; primary and secondary, 9, 308; proportioning of partial, iv, 300-1; protection against overloaded, vii, 34-50 Circular Mils, iv, 282-3, 382 Circular Reflex, xi, 42; in habit formation, 252-3