186 REPORT — 1855. 



well-known long-established moneys, both of account and circulation. That they 

 never will consent and never can be made to consent, to having either their pence or 

 their pounds interfered with, and superseded as has been proposed — in order to in- 

 troduce, at vast expense and inconvenience, a troublesome, complicated, imperfectly 

 decimal, and utterly isolating system, both of accounts and coinage — when the most 

 useful, comprehensive, and perfect of all possible decimal systems can, at any moment, 

 be introduced and rendered general, without losing any one of the tiseful desirable ob- 

 jects and applications of either the pound, the penny, or any other existing coin, with- 

 out expense, and without the transition being embarrassed by more than a scarcely 

 perceptible amount of change. 



On the Progressive Rates of Mortality, as occurring in all ages ; and on 

 certain Deviations. By John Reid, Surgeon, Glasgow. 



An individual living to the age of 100 years, would live over the whole breath- 

 ing-time represented in the accompanying Table ; which shows columns numbering 

 100 years from left to right, and a scale marking the same from top to bottom. 

 According to both ancient and modern computation, there are three generations in 

 every 100 years, i. e. the whole population is renewed every 33^ years ; but 

 the length of a generation varies in different kinds of population. It ought to be 

 longer amongst the better living classes than amongst the poor and improvident, 

 also in some families than in others, the individuals of some families being longer 

 lived than those of others. In England and Wales the mean duration of life, which 

 measures the length of a generation, is about 35^ years, but it is generally reckoned 

 at about 33 only, which is the probability , expectancy or value of life at birth. From 

 this point we start in estimating the value of life either at the particular ages, or 

 throughout the different periods ; such estimation being generally made on a given 

 number of lives, the ages of the different individuals having been ascertained as cor- 

 rectly as possible at their deaths. Such having been ascertained, say of 10,000, the 

 number dying at the different ages, or betwixt every five years, will represent the 

 proportional mortality or the per-centage of deaths ; so upon finding that of 10,000, 

 we infer it to be a fair criterion in estimating the per-centage over a whole popula- 

 tion. In the Table the value of life at birth is shown to be 33 years on the scale, 

 i.e. taking off 67 years from the 100 ; now, during the first five years, of 10,000 

 born, 3900 die, or 36^^ per cent. ; during the next, or second five years, only 460 die, 

 or A\ per cent. A child having lived five years has passed through the most dan- 

 gerous period ; its probability of life is therefore greater than it was at birth, and is 

 represented in the Table at 48 years, which was long considered the maximum value 

 of life according to the average of life tables. But the average of the Registrar- 

 General's Reports shows the greatest probability to be at the age of nine, so in 

 adopting this still greater decline, the value of life at that age is 54 years, which is 

 perhaps rather too high ; but we have a still higher probability on the Table, viz. 

 58 years, which is shown at the age of 13. 



Starting from either of these epochs, we find certain rates of mortality occurring 

 in the different periods of life, deduced from the deaths at the different ages. As 

 the average of the Registrar-General's Reports must be nearest the truth, we will 

 take the age of nine as representing the greatest probability of life, that almost gra- 

 dually decreasing with advancing age. The figures above the diagonal line on the 

 Table, show the probability of life at the different ages ; e. g. at the age of twenty- 

 five, it is 42 years ; at fifty, 25 ; at sixty-five, 15 ; at eighty, 5 ; and at a hundred, 

 1^ year. And it may be observed that at the age of thirty-seven it is 33 years, being 

 the same as at birth. 



It is somewhat surprising how little deviation there is in the different periods of 

 life, excepting infancy and early childhood, and extreme old age. The ascent, from 

 the age of nine' to death, is but a slightly deviating rise to the extreme age of eighty, 

 showing the natural inherent powers in man to pass the threescore years and ten ; 

 and if his bodily functions were not deranged in the course of life from many different 

 exciting causes, death in the intervening periods would be an exception only to that 

 in old age, occurring from the gradual tear and wear of structural parts. 



Dr. Buchanan's table shows the number of deaths in the living at the different 



