Burbank,[230] an American horticulturist, has recently gained a wide reputation because of his improvements of useful plants. He has produced a new kind of potato which has raised the value of potato crops in the United States by about £3,500,000 per annum. Burbank cultivated great numbers of fruit trees, flowers, and all kinds of plants, with the object of increasing their utility. One of his objects was to produce varieties which could resist dry conditions, which reproduced rapidly and so forth. He has modified the nature of plants to such an extent that he has cactus plants and brambles without thorns. The succulent leaves of the former provide an excellent food for cattle, whilst the absence of thorns in the latter makes their pleasant fruit more suitable for gardens. Burbank has enormously improved the production of stoneless plums, and has very much reduced the price of many bulbs and lilies by increasing their productivity. To obtain such results much knowledge and a long period of time were necessary. To modify the nature of plants it was necessary to understand them well. To frame the new ideal of the plant it was necessary not only to have an exact conception of what was wanted, but to find out if the qualities of the plants in question furnished any hope of realising it. The methods which have been successful in the case of plants and animals must be much modified for application to the human race. In the case of human beings the selection and cross-breeding which were imposed upon rye and plum trees are not possible, but, at the same time, the ideal of human nature, towards which mankind ought to press, may be formed. In our opinion this ideal is orthobiosis, that is to say, the development of the human life so that it passes through a long period of old age in active and vigorous health, leading to the final period in which there shall be present a sense of satiety of life, and a wish for death. I do not think that the ideal should be that of Herbert Spencer, a simple prolongation of human life. When the instinct of death comes at a not very late period of life, there would be no inconvenience in shortening the life, if death did not come soon after the appearance of the instinct. Probably this would be the only case where suicide was justified in the conception of orthobiosis.