but, of course, not less than that of the ‘population as a whole.’ And, to continue with the main argument, if we wish to investigate the longevity of shoemakers we should again have to decide upon some age at which on the average a person has probably already acquired the dexterity requisite to be a shoemaker. Even if we fix this so low as ten years, at which time the expectation of life is forty-eight years, it would bring the average age at death of shoemakers to fifty-eight years. It has thus become extremely obvious that if we compared these ages at death with the average life-period it would be just as easy to prove that lawyers and shoemakers and merchants enjoy exceptional longevity, as to prove that great men do. The average longevity is low because of the very large infant mortality, which enters into the composition of this average. When once the first ten years of life are passed the further expectation of life increases quite slowly. Roughly speaking, for every ten years between ten and fifty years the added expectation of life is but three years for each decade. We therefore see that in the very nature of things no one class of adults can possibly live as much as thirty years longer than ‘the population as a whole.’ The differences with which we are dealing are differences of a finer order, of a small number of years, and being slight differences, must be substantiated by a relatively large number of cases; the cases, moreover, must be collected in a wholly unobjectionable manner; that is, in a manner in which the principle of selection bears no influence upon the longevity. To my knowledge adequate statistics which exhibit the relative longevity of different classes do not exist, and they certainly do not exist with regard to great men. We may therefore conclude that the facts which have thus far been collected are not opposed to the conclusion that great men enjoy favorable longevity, but they certainly have not established or contributed to the establishment of this fact. While it is not impossible to collect material which may serve as corroborative evidence of the longevity of great men, it seems probable that we must be content with evidence of a far inferior character.