Ants, Mr. Darwin says they "communicate information to each other, and several unite for the same work, or games of play. They recognize their fellow-ants after months of absence. They build great edifices, keep them clean, close the doors in the evening, and post sentries. They make roads, and even tunnels under rivers. They collect food for the community, and when an object too large for entrance is brought to the nest they enlarge the door, and afterwards build it up again. They go out to battle in regular bands, and freely sacrifice their lives for the common weal. They emigrate in accordance with a preconcerted plan. They capture slaves. They keep aphides as milch cows. They move the eggs of their aphides, as well as their own eggs and cocoons, into warm parts of the nest, in order that they may be quickly hatched; and endless similar facts could be given." It is incredible to suppose that animals could accomplish such feats without mind of some kind.
The brain of the Fish is small compared to the spinal cord of which it is the continuation, and the parts of which it is composed are so arranged that no one part obscures the other. In Reptiles the brain is larger, and the Cerebral Hemispheres, the seat of the higher mental activities, slightly predominate over the other parts of the brain. This peculiarity becomes more marked in the Birds; while the Cerebral Hemispheres of the lower mammalia, like the Ornithorhynchus and the Opossum, quite overlap parts perfectly visible in the Fish. Ascending through the orders of the Mammalia, the Cerebral Hemispheres continue to overlap the other parts of the brain, until finally in the higher Apes and Man they entirely cover the Cerebellum, Medulla Oblongata, etc. By comparing the mental powers of the different Vertebrata, we see that the gradual development of the brain is accompanied by a corresponding development of mind. The low grade of intelligence of the
