Vol.. 8, 1922 STATISTICS: PEARL AND BURGER 73 
TABLE 2 
Grouped Data for Vital Index and Crude Birth Rate 
PERIOD 
BIRTH 
DEATHS 
100 BIRTHS 
DEATHS 
GENERAL 
BIRTH RATE 
PER 1000 
1838-1839 
956,361 
681,744 
140.28 
31.0 
1840-1844 
2,600,288 
1,756,431 
148.04 
32.2 
1845-1849 
2,797,329 
2,003,657 
139.61 
32.6 
1850-1854 
3,080,095 
2,030,528 
151 .69 
33.9 
1855-1859 
3,300,929 
2,126,461 
155.23 
34.3 
1860-1864 
3,560,830 
2,263,769 
157.30 
34.9 
1865-1869 
3,830,527 
2,438,121 
157.11 
35.3 
1870-1874 
4,100,856 
2,541,625 
161.35 
35.5 
1875-1879 
4,399,070 
2,623,391 
167.69 
35.6 
1880-1884 
4,451,771 
2,591,038 
171.81 
33.8 
1885-1889 
4,450,173 
2,620,108 
169.85 
32.0 
1890-1894 
4,486,912 
2,778,642 
161.48 
30.5 
1895-1899 
4,611,116 
2,771,151 
166.40 
29.6 
1900-1904 
4,691,038 
2,739,365 
171 .25 
28.5 
1905-1909 
4,637,271 
2,613,992 
177.40 
26.7 
1910-1914 
4,411,823 
2,519,713 
175.09 
24.2 
1915-1919 
3,623,894 
2,685,456 
134.95 
20.8 
1920 
957,994 
466,213 
205.48 
25.5 
since the Middle Ages, furnish a substantial demonstration of the fact 
that population growth is a highly self -regulated biological phenomenon. 
Those persons who see in war and pestilence any absolute solution of the 
world problem of population, as postulated by Malthus, are optimists 
indeed. As a matter of fact, all history definitely tells us, and recent his- 
tory fairly shouts in its emphasis, that such events make the merest ephem- 
eral flicker in the steady onward march of population growth." 
In view of the fact that this function V has so quickly returned to nor- 
mal, or approximately normal, values after the recent disturbances it is 
a matter of considerable interest and significance to the student of problems 
of public health in the broad sense, of population growth, and of human 
ecology, to see how precisely the self -regulatory mechanism of populations 
operates over long periods of time. To this end we have examined all the 
existing continuous statistics of England and Wales, and desire to present 
the results in this paper. 
Table I gives the vital index (100 births/deaths) for the population of 
England and Wales, in each quarters of the years 1838 to 1920 inclusive. 
The data from which the computations were made were taken from official 
sources.^ 
The immediately striking feature of this table is the extreme constancy 
of the values as one runs down the columns. In order to appreciate this 
fact fully, however, it is necessary to resort to graphical presentation. 
x\s the data of table I are too detailed to make such an examination of 
