With CONSCIOUSNESS the case is very different. Its phenomena are not comparable with those of any kind of _matter_ subjected to any of the known or conceivable _forces_ of nature; and we cannot _conceive_ a gradual transition from absolute unconsciousness to consciousness, from an unsentient organism to a sentient being. The merest rudiment of sensation or self-consciousness is infinitely removed from absolutely non-sentient or unconscious matter. We can conceive of no physical addition to, or modification of, an unconscious mass which should create consciousness; no step in the series of changes organised matter may undergo, which should bring in sensation where there was no sensation or power of sensation at the preceding step. It is because the things are utterly incomparable and incommensurable that we can only conceive of _sensation_ coming to matter from without, while _life_ may be conceived as merely a specific combination and co-ordination of the matter and the forces that compose the universe, and with which we are separately acquainted. We may admit with Professor Huxley that _protoplasm_ is the "matter of life" and the cause of organisation, but we cannot admit or conceive that _protoplasm_ is the primary source of sensation and consciousness, or that it can ever of itself become _conscious_ in the same way as we may perhaps conceive that it may become _alive_. INDEX. _ABRAXAS grossulariata_, 119. _Acanthotritus dorsalis_, 94. _Accipiter pileatus_, 107. ACRAEIDAE, the subjects of mimicry, 85, 86. _Acronycta psi_, protective colouring of, 62. ADAPTATION brought about by general laws, 276; looks like design, 281. AEGERIIDAE mimic Hymenoptera, 90. AGASSIZ, or embryonic character of ancient animals, 301. _Agnia fasciata_, mimics another Longicorn, 95. _Agriopis aprilina_, protective colouring of, 62. ALCEDINIDAE, sexual colouring and nidification of, 240. AMADINA, sexual colouring and nidification of, 243. AMPELIDAE, sexual colouring and nidification of, 243. ANCYLOTHERIUM, 300. ANDRENIDAE, 98. _Angraecum sesquipedale_, 272; its fertilization by a large moth, 275. ANIMALS, senses and faculties of, 127; intellect of, compared with that of savages, 341. ANISOCERINAE, 92. ANOA, 196. ANOPLOTHERIUM, 299. ANTHRIBIDAE, mimicry of, 94; dimorphism in, 155. _Anthrocera filipendulae_, 120. ANTHROPOLOGISTS, wide difference of opinion among, as to origin of human races, 304; conflicting views of, harmonized, 321. ANTIQUITY of man, 303, 322. APATHUS, 98. APPARENT exceptions to law of colour and nidification, 253. AQUATIC BIRDS, why abundant, 32. _Araschnia prorsa_, 154. ARCHEGOSAURUS, 300. ARCHAEOPTERYX, 300. ARCHITECTURE of most nations derivative, 228; Grecian, false in principle, 226. ARCTIC animals, white colour of, 50, 51.