of which has attained a higher longevity; yet it is certain that a degree of longevity never yet witnessed has always been attainable, because such longevity depends on conditions which are now known--conditions entirely within human control. I have said that there is involved in the mere length of life a larger and higher boon than is apparent without reflection. First, because length of life is in general a tolerably accurate measure of the amount of health, without a good share of which life is comparatively worthless. The instances are rare in which a person attains to old age who has not enjoyed at least a moderate share of daily health and vigour. Secondly, because length of life is a perfectly accurate measure of the amount of enjoyment. Long life is incompatible with a condition of constant privation and wretchedness. It is one of the beneficences of the constitution of our nature that when the balance of happiness is against us, a limit is fixed to our misery by its rapid termination in the insensibility of death. In the very brevity of its existence, therefore, a human being indicates his own history for evil; the shortness of his life is the sure and correct index of the amount of his suffering, physical and mental: it is the result, the sum-total, the aggregate expression, of the ills endured. Thirdly, because length of life is the protraction of that portion of life, and only of that portion of it, in which the human being is capable of the greatest degree of usefulness. I have elsewhere shown that every year by which the term of human life is extended is really added to the period of mature age; the period when the organs of the body have attained their full growth and put forth their full strength; when the physical organisation has acquired its utmost perfection; when the senses, the feelings, the emotions, the passions, the affections are in the highest degree acute, intense, and varied; when the intellectual faculties, completely unfolded and developed, carry on their operations with the greatest vigour, soundness, and continuity: in a word, when the individual is capable of communicating, as well as of receiving, the largest amount of the highest kind of happiness.