Thus either man to-day is constitutionally fitter to survive or else he has made himself better conditions up to about the seventh decade. The reason why expectation increased after that period is because conditions were so unfavorable that all but the very most rugged succumbed earlier in life and the proportion of those who reached advanced age was far less than now. In Rome, during the first three or four centuries of the Christian era, the expectation was less yet until nearly sixty, after which it rose, and it is significant that expectation of life was far less under the conditions then prevailing for women than for men at all ages of life, which is the reverse of conditions now prevailing. In the Roman provinces, however, expectation was greater than in the Eternal City. In the Roman-African population, although there was greater mortality to about forty, expectation of life was superior after that age in the early part of the Christian era to what it now is. In considering life tables that give the number of deaths occurring at each age, which give an S-shaped curve falling very rapidly before the end of the second year and reaching its highest subsequent point at seventy, Karl Pearson finds in this S-shaped curve five components which he typifies as five Deaths shooting with different weapons and with differing precision as the procession of human beings crosses the Bridge of Life. The first Death is a marksman of deadly aim and unremitting diligence who kills before as well as after birth. The second, who aims at childhood, has a very concentrated fire. The third, who shoots at youth, has not a very deadly or accurate weapon but one rather to be compared with a bow and arrow. The fire of the fourth marksman is slow, scattered, and not very destructive, as if from an old-fashioned blunderbus. The last Death plies the rifle, which none escape. Pearl justly criticises this conception because “no analysis of the deaths into natural divisions by causes or otherwise has yet been made such that the totals in the various groups would conform to these frequency curves.” Thus he holds that Pearson’s concept of the five deaths does not represent any biological reality but only demonstrates, as any other equally successful curve would do, that deaths do not occur chaotically but instead “in a regular manner capable of representation by mathematical function in respect of age.” II