The index of correlation[191] between the lengths of life within the fraternity in these 100 selected families, furnished a coefficient of-.0163+-.0672, practically zero. In other words, if the age is known at which a member of one of these families died, whether it be one month or 100 years, nothing whatever can be predicted about the age at which his brothers and sisters died. Remembering that longevity is in general inherited, and that it is found in the families of all the people of this study (since one in each fraternity lived to be 90 or over) how is one to interpret this zero coefficient? Evidently it means that although these people had inherited a high degree of longevity, their deaths were brought about by causes which prevented the heredity from getting full expression. As far as hereditary potentialities are concerned, it can be said that all their deaths were due to accident, using that word in a broad sense to include all non-selective deaths by disease. If they had all been able to get the full benefit of their heredity, it would appear that each of these persons might have lived to 90 or more, as did the one in each family who was recorded by the Genealogical Record Office. Genetically, these other deaths may be spoken of as premature. In an ordinary population, the age of death is determined to the extent of probably 50% by heredity. In this selected long-lived population, heredity appears not to be responsible in any measurable degree whatsoever for the differences in age at death. The result may be expressed in another, and perhaps more striking, way. Of the 669 individuals studied, a hundred--namely, one child in each family--lived beyond 90; and there were a few others who did. But some 550 of the group, though they had inherited the potentiality of reaching the average age of 90, actually died somewhere around 60; they failed by at least one-third to live up to the promise of their inheritance. If we were to generalize from this single case, we would have to say that five-sixths of the population does not make the most of its physical inheritance. This is certainly a fact that discourages fatalistic optimism. The man who tells himself that, because of his magnificent inherited constitution, he can safely take any risk, is pretty sure to take too many risks and meet with a non-selective--i.e., genetically, a premature--death, when he might in the nature of things have lived almost a generation longer.