In the Sixty-fifth Report (1909) of the Commissioners in Lunacy for England and Wales, the following observations were made in respect of the incidence of cancer in mental hospitals and in the general population:

“There remains one morbid condition which is responsible for an increasing number of deaths in the general community, from which it would almost appear as if the insane enjoyed some immunity. According to these figures, the proportion of deaths from “cancer,” i.e., from all forms of malignant disease, was in asylums 36.4 per 1,000, which may be compared with the ratio of 99.4 per 1,000 in the rest of the community, the disparity being more marked in the female than in the male sex. Although the mortality-rates per 1,000 living show a rate of 2.98 amongst the insane, and of 1.39 in the others, yet having regard to the great divergence between the general death-rates in the two series, the general cancer mortality in relation to that of the insane is not 1.39, but 8.11. Upon what can this difference depend? Is it because, as suggested in the analogous case of bronchitis, the asylum patient is protected from some unknown factor in the development of this disease; or has it to do with mode of living as well as of environment; or can it be that there is any antagonism between the conditions favourable to the development of cancer and those which conduce to insanity? At any rate, in view of these statistics, which seem valid and are confirmatory of those we published two years ago, a thorough investigation of the subject might not be without profit.”