as old men do, and that therefore auto-suggestion plays a less powerful part with them. [Illustration: FIG. 5.--Thomas Parr. Reputed to have lived 152 years (1483–1635). From a Print by Payne.] The question must arise as to what is the object of the prolongation of life after the reproductive function has waned as it does in women--the more long-lived of the sexes--about half-way through the physiological term of years. In some lower animals life terminates very shortly after propagation of the species has been effected; but this is not the rule, and the biological meaning of the continuation of the life of individuals that but cumber the ground and may lead a parasitic existence requires explanation, though educational advantages and moral lessons may undeniably be provided by healthy old age with its store of what a Cambridge man, now justly famous, described in his rather rebellious youth as “that greatly over-rated property experience.” It has been suggested by Sir Ray Lankester that the inherent property resulting in longevity may be bound up as a “correlated variation” with some other characteristic useful in the struggle for existence and the perpetuation of the species. An obvious possibility is that the long-lived have a higher fertility rate than average mortals. Hufeland[34] argued that as very old people are nearly always married more than once and generally at a very late period of life “a certain abundance in the power of generation is favourable to longevity.” There are few satisfactory data to determine the converse proposition with which we are now concerned, namely, is longevity accompanied by unusual fertility? As already mentioned, the great majority of centenarians are found among the bulk of the population, namely the poor, who are far more prolific than the well-to-do; but this does not prove much, for the inverse correlation of fertility and good social status is largely artificial and due to voluntary birth control. Among the 824 persons between 80 and 100 years of age analysed by Sir George Humphry[35] in 1889 there were 335 married men and 292 married women, and in each group the average number of children was six, which is somewhat in excess of what is popularly supposed to be the average size of a family; but the question of average fertility is one on which Dr. Major Greenwood warns me that it is difficult to give an unambiguous answer, for it all depends on whether completed or incompleted fertilities are meant; thus in the 1911 census the completed fertilities average 5·8 and the uncompleted 4·2. No value could, he considers, be attached to the general figure obtained by dividing the total number of children by the total number of couples enumerated. Hence Sir George Humphry’s and other statistics are not really comparable. While finding that longevity was equally shared by the single and married women and by those who had children and by those who were barren, Sir George Humphry stated that among those who had