TRANSACTIONS OF THE SECTIONS. 161 



The best mode of exhibiting the law of mortality, according to age, in its details, 

 is by means of tables or diagrams indicating the ages at which the deaths in a large 

 community, where the number of the people is known, have been observed to take 

 place. The most useful tables of this kind for physiological purposes exhibit the 

 same number of individuals entering on each year of life, and in the earlier years 

 upon lesser periods, and determine the proportion of them which disappear by death 

 in each year or lesser period. 



The following Table, computed from a table of a different form, published in the 

 Fifth Report of the Registrar- General for 1843, exhibits the law of mortality which 

 prevails in England for a sufficient number of ages to show its general course, — • 

 diminishing gradually till 13 years of age, and gradually increasing after that age : 



The numbers in this Table denote the average mortality for a whole year ; but 

 during the greater part of life no great error arises from employing the same num- 

 bers to denote the relative rates of mortality for any lesser periods in the same year, 

 although, strictly speaking, each number in the Table belongs only to one such period, 

 and all the rest have numbers either above or below that in the Table. This differ- 

 ence is so great in the first years of life, that separate observations require to be 

 made to determine the rate of mortality at different parts of them. The following 

 table of this kind stops short where it becomes identical with the former table, 

 from its being unnecessary to distinguish the different rates of mortality at different 

 parts of the same year. The numbers, properly speaking, denote the deaths at each 

 age out of 10,000 children in 3-65 days, or the hundredth part of a year : — 



First week 240-1 Second half-year 121 



Second to fourth week 80 Third ditto 10-7 



Second montli 35-3 Fourth ditto 7*7 



Fourth ditto 21-9 Third year 3-3 



Sixth ditto 16-2 Sixth ditto 1-4 



For indicating these minute differences a diagram is much superior to any Table ; 

 for everv term in the Table merely denotes the length of a single ordinate to the 

 " curve of mortality," and when a sufficient number of terms have been obtained to 

 admit of the accurate delineation of the curve, every other ordinate to the period to 

 which it corresponds can be readily found. 



II. The second part of the memoir, to which the first was intended as an intro- 

 duction, was devoted to the consideration of certain anomalies in the course of mor- 

 tality that present themselves at the commencement of adult life. 



The anomalies in question were first pointed out in Mr. Finlayson's Report on the 

 Mortality among the Government Annuitants, published in the year 1829, a Report 

 of great interest, as exhibiting the law of mortality that prevails among " the highest 

 and most affluent orders of society" in this country. Among them the mortality in 

 the male sex exhibits this peculiarity : — starting from 13 years of age, the point of 

 greatest security of life, the mortality increases till the age of 23, after which, 

 instead of continuing to increase, it decreases till the age of 34, and then it increases 

 at so slow a rate that at the age of 48 it is still somewhat less than at 23. The rates 

 of mortality at these remarkable epochs are as follows, contrasting them with the 

 corresponding rates in the table given above : — 



1855. 11 



