180 Oti Criteria for the Existence of Diferential Deathrates 
corresponds to the 55 to 65 group. In fact in the case of London and Rural 
Districts about three-fourths and in the case of County Boroughs and Rural 
Districts about four-fifths of the value of are contributed by the age groups 
45 to 65. This is not the period in which the total number of deaths from cancer 
is a maximum ; it may therefore be the period in which the less skilled medical 
man is less likely to diagnose cancer. It would be equally valid, however, to 
assert that cancer finds more susceptibility in town than in country dwellers and 
that this is particularly the case with men from 45 to 65 years of age. Further 
suggestions are, of course, emigration of cancerous persons to the towns* and 
the presence of certain occupations with high cancer deathrates in the towns. 
In both these cases we must find explanation for the particularly marked contribu- 
tions for the age groups 45-65, unless we are content with the view that these are 
the age groups where the cancer deathrates are fairly high, and the population of 
the group with which the result is weighted fairly large. 
It would be in every way desirable if we could, applying "Occam's razor," 
attribute to one source the rising cancer deathrate and the significant differences 
between cancer mortality in cities and in rural districts. Both may be due to 
differential diagnostic power or to varying accuracy of certification, but we gain 
little by merely throwing out suggestions, and omitting to demonstrate them. 
(ix) — (xiv) Diabetes Deathrates for all England and Wales. 
As a last illustration of the present method we take the deaths from Diabetes 
for the year 1913 from the Registrar-General's Rejwrt'f in the same fundamental 
groupings ; of course the pojDulations at risk in age groups will remain the same. 
Diabetes Deaths in Age Groujjs, 1913. 
Age Group 
(a) London 
(6) County 
(c) Urban 
(d) Rural 
Boroughs 
Districts 
Districts 
0—15 
8 
22 
22 
26 
15—25 
12 
35 
46 
38 
25—35 
20 
60 
69 
38 
35—45 
21 
63 
66 
44 
45—55 
49 
86 
102 
51 
55—65 
59 
158 
196 
106 
65—75 
47 
178 
181 
137 
75—85 
16 
47 
57 
50 
85 and over 
0 
5 
6 
1 
Total Deaths 
232 
654 
745 
491 
Crude deathrates 
10-930 
11-700 
12-051 
12-392 
Corrected deathrates 
11-099 
12-649 
12-433 
10-948 
(Both per 100,000) 
* It must be remembered of course that institutional deaths are since 1911 distributed to their locus 
of origin, and tlierofore immigration for operation no longer tends to swell the London or County- 
Boroughs cancer deathrates. It would be otherwise with immigration for permanent residence in the 
initial stages of the disease. But there is no evidence at present to show that cancerous persons of 
ages 45 to 05 do move into the larger towns. "I" See pp. 217, 235, 253 and 271. 
