Metchnikoff suggests that it is a poison formed in the plant (in connection with fructification?) which kills the annuals, while it is not formed or is less harmful in the perennials. He compares the situation to the death of the lactic acid bacilli if the lactic acid is allowed to accumulate. This hypothesis is certainly worthy of consideration, and it is quite possible that in addition to structural shortcomings poisons formed by certain organs of the body as well as poisons formed by bacteria account for the phenomenon of death in metazoa. INDEX _Abraxas_, 203, 238, 241 Acquired characters, inheritance of, 337 ff. _Actinia equina_, 361 Adaptation, 12, 318 ff.; to life in caves, 319 ff.; fresh and salt water, 327 ff.; poisons, 332 ff.; temperature, 334 ff.; caused by hormones, 342 Addison, W. H. F., 188 Agglutination, of corpuscles by sera, 67 ff.; of sperm, 78, 82 ff. _Allolobophora terrestris_, 46 _Alpheus_, 176 _Alytes obstetricans_, 337, 338 _Amanita phalloides_, 63 _Amblystoma_, 157, 368 Amelung, 184 _Amphipyra_, 283 Analogies between living and dead matter, 14 ff. Anaphylaxis reaction, 61 ff. Ancel, 158, 225 ff. Antagonistic salt action. _See_ Balanced salt solutions. _Antennularia antennina_, 194, 196 Apes, blood relationship to man, 54, 56 ff. Apolant, 45 _Arbacia_, 75 ff., 96, 99, 101, 111, 114, 150, 190 ff., 293 ff., 298, 299, 364 _Arenicola_, 277 Armstrong, E. F., 26, 28, 354 Arrhenius, S., 33 ff., 88, 290, 296 Arrhenoidy, 218, 225 Artificial parthenogenesis, 95 ff.; in sea urchins, 95 ff.; new method of, 98, 99; by blood, 101 ff.; by sperm extract, 103; by acids, 105; by mechanical agitation, 107; in starfish, 110; rôle of hypertonic solution, 112, 115, 116; and oxidation, 116, 117, 118; and permeability, 119 ff.; in frogs, 124; and determination of sex, 125 Artificial production of life, 38-39 Assimilation of CO₂ without chlorophyll, 17 ff. _Asterias_, 49, 81, 110, 363; _ochracea_, 73 ff.; _capitata_, 74 _Asterina_, 75, 81, 110 Astrospheres, 115 ff., 192 Auer, J., 315 Autolysis, 351 ff. _Avena_, 263 _B. coli communis_, 36; _typhosus_, 36; _fluorescens_, 334 Bacteria, growth of, 15 ff., 29, 71 ff.; specificity in, 41 ff. “_Bacterio-purpurin_,” 41 Balanced salt solutions, 307-317; theory of, 317; and adaptation, 331 ff. _Balanus_, 259 Baltzer, F., 215 ff. Bancroft, F. W., 70, 125, 127, 264, 269 ff. Bang, 63 Bardeen, C. R., 174 ff. Barnacle, larvæ of, 313 ff. Bataillon, 124 Bateson, W., 230, 240 ff., 338, 348 _Batrachia_, 338 Baur, E., 48, 246 Bayliss, 63 Becquerel, P., 36 ff. _Beggiatoa_, 19 Beijerinck, M., 20 Berkeley, Lord, 111 Bernard, Claude, 2 ff., 26, 159, 350, 354, 355, 358 Berthelot, 290 Bertrand, G., 248 ff. Beutner, R., 140