On the other hand, the knowledge that the goal of human life can be attained only by the development of a high degree of solidarity amongst men will restrain actual egotism. The mere fact that the enjoyment of life according to the precepts of Solomon is opposed to the goal of human life will lessen luxury and the evil that comes from luxury. Conviction that science alone is able to redress the disharmonies of the human constitution will lead directly to the improvement of education and to the solidarity of mankind. In progress towards the goal, nature will have to be consulted continuously. Already, in the case of the ephemerids, nature has produced a complete cycle of normal life ending in natural death. In the problem of his own fate, man must not be content with the gifts of nature; he must direct them by his own efforts. Just as he has been able to modify the nature of animals and plants, man must attempt to modify his own constitution, so as to readjust its disharmonies. Breeders form a conception of the ideal result when they are about to attempt the production of some new variety which shall be pleasing esthetically and of service to man. Next, they study the existing individual variations in animals and plants on which they wish to work, and from which they will select with the minutest care. The ideal result must have some relation to the constitution of the organisms selected. To modify the human constitution, it will be necessary first, to frame the ideal, and thereafter to set to work with all the resources of science. If there can be formed an ideal able to unite men in a kind of religion of the future, this ideal must be founded on scientific principles. And if it be true, as has been asserted so often, that man can live by faith alone, the faith must be in the power of science. INDEX Abortion, artificial, 102, 103, 104, 105 as a religious ceremony, 164 Abstinence, Hartmann on sexual, 186 Aged, fear of death by, 131 murder of, by low races, 129, 130 treatment of, by modern society, 130 Albius, and artificial fertilisation, 20 Alcohol, and length of life, 259 as producer of sclerosis, 247 Altruism, limitations of, 296 Anæsthetics, influence of, compared with death, 159 Ancestor-worship, in China, 144 by Confucius, 145, 146 by Kaffirs, 150 quotations from Tylor on, 150 Animism, Tylor on, 138, 139, 140 _Anisoplia_ and light, 36 Annelids, vegetative reproduction of, 264 Annihilation, Büchner on, 220 Mailaender on, 188 Anthropoid apes, relationship to man, 55 social instincts of, 105 Ants, sexual disharmonies in, 34 Apes, compared with man, 42, 43 Appendage, vermiform, of man and apes, 44 Appendicitis, 66, 67 curable by modern science, 211 frequency of, 68 Apoplexy, phagocytes in, 239 Aristotle, on future life, 169 on pleasure, 6 Art, as affected by Christianity, 13 of the Greeks, 5 Arterial sclerosis, 247