Then, too, immediate environment plays a part. The savage often has no idea of contagion, and still less of guarding against it; he thinks in terms of magic instead of physiology—and succumbs. How far heavy mortality is the result of lack of resistance or of fundamentally vicious treatment, is often hard to say. If we tried to cure smallpox by subjecting patients to a steam-bath and then having them plunge into a wintry river, we should perhaps look upon the disease as a very nearly fatal one to the Caucasian race.
39. Causes of Cancer Incidence
It may be worth while to consider briefly the facts as to mortality from cancer. This dread disease appears to be not contagious, so that the factor of acquired immunity is eliminated. It is regarded as incurable, except by operation, so that differences in treatment become relatively unimportant. If therefore significant differences in racial liability to cancer exist, they should emerge with unusual clearness and certainty.
At first sight they seem to. It has been alleged that the white race is the most susceptible to this affliction. The supporting figures are as follows: cancer deaths per year per 100,000 population.
It would seem from these figures that Caucasians die more frequently of cancer than members of the darker races. In fact, this has been asserted. Let us however continue with figures.
| 1908-12 | Large cities, latitudes | 60°-50° North | 106 |
| 50°-40° ” | 92 | ||
| 40°-30° ” | 78 | ||
| 30° North-30° South | 38-42 | ||
| 30°-40° South | 90 |
This table would make cancer mortality largely a function of geographical latitude, instead of race.
Another factor enters: occupation. The following data give the death rate per 100,000 population among males of 45-54 in England and Wales.
| 1890-92 | 1900-02 | |
|---|---|---|
| Lawyers | 199 | 159 |
| Physicians | 102 | 121 |
| Clergymen | 81 | 91 |
| Chimneysweeps | 532 | 287 |
| Brewers | 190 | 239 |
| Metal workers | 120 | 137 |
| Gardeners | 88 | 93 |
| All occupations | 118 | 145 |