Page:Popular Science Monthly Volume 19.djvu/648

630 length of life is merely an expression of the sum total of social influences upon the organism. A community may be divided into ever so many groups, each of which will have its peculiarity, and the summary of all these units will give as resultant the average of life. Every graduated mortality table may, therefore, be considered only an approximate expression of the death-rate under the conditions and at the time of observation.

We may now follow "English Life Table No. 3" more in detail. It gives a separate record of both male and female life, and we may examine the mortality of males first.

The notation adopted refers to the percentage of death in the current year; meaning from birth to end of first year, 1 from beginning to end of second year of life, and so on:

Let us now compare male and female mortality. There are born 511,745 males to 488,255 females, being an excess of 23,490 males $$=$$ 4·81 per cent.