The inordinate frequency with which carcinoma attacks the alimentary canal naturally suggests that the infective agent, if such there be, is usually introduced into the body with the food. It is therefore necessaiy to inquire whether indulgence in or abstinence from some particular article of diet exerts any decided influence upon its development. Reclus and others appear to have convinced themselves that those who live upon vegetables are practically exempt from the disease, but the evidence upon which this belief is founded is somewhat obscure. On the other hand, there are strong reasons for believing that the exclusive use of vegetables does not prevent the inception of cancer. Hendley states that out of 102 patients who were operated upon for carcinoma at Jeypore between 1880 and 1888, sixty-one were lifelong vegetarians ; while nearly 3 per cent, of our cases of gastric carcinoma denied that they had eaten meat for many years. In private practice we have also frequently observed the disease in people who had long abstained from animal food. The popular superstition that tomatoes give rise to cancer is probably founded upon some fancied resemblance between the interior of the vegetable and a fungoid growth. Other authorities attribute the increase of carcinoma to the greater consumption of meat by the population during the last halfcentury. It can hardly be denied that the tendency to luxurious living has increased in almost every country in the last fifty years, but that excessive indulgence in meat is a primary factor in the production of the disease has yet to be proved. It may be noted that the liability to cancer of the stomach increases with age, whereas the appetite for meat usually diminishes after middle life. Moreover, it is almost unknown among savage tribes, who live by hunting, and among the Esquimaux, while it is common both in hospitals and infirmaries, whose sick inmates have seldom enjoyed opportunities for over-indulgence in meat.
1 In this table the mortality of all males from twenty-five to sixty-five years of age from all causes is taken as a standard - 1,000. Out of this number the deaths from cancer in all males amount to forty-seven. The table gives the comparative numbers for males in different occupations, these numbers having only a relative, and not an absolute, value.
Again, there is no evidence to show that any special variety of animal food promotes the development of the complaint. Dried and tinned foods are apparently harmless, and Bauby has shown that pork-eaters are not more prone to the disease than others. It has been suggested that the importation of frozen mutton might be responsible for the increasing prevalence of malignant disease in Europe ; but the comparative immunity enjoyed by the native populations of Australia and Argentina, and the uniform increase of the disease in all parts of the civilised world, are sufficient to negative this supposition.
Fishermen in England are unduly prone to cancer, hut this can hardly be ascribed to their diet, since the disease is very common in the Black Forest and other parts of Central Europe where fish is a rare article of food.
It is often asserted that teetotalers are seldom affected by carcinoma, but we are not aware of any authentic evidence in support of this view. On the contrary, we find that nearly 40 per cent, of our cases at the London Temperance Hospital were total abstainers; while at the London Hospital, where patients are very seldom given to abstinence, no less than 4 per cent, of the cases of gastric cancer affirmed that they had been lifelong abstainers from alcohol. It may also be noted that malignant disease is very common among the Mohammedan population of India, who never indulge in alcohol; while the British Medical Association's report upon the etiology of cancer indicates that the alcoholic habit is, if anything, antagonistic to the development of carcinoma. Lastly, Boger Williams has laid great stress upon the tendency of the complaint to attack people who have led sober and industrious lives, and upon the comparative immunity of those of debauched and dissolute habits. We are also convinced that the gastric lesion is extremely rare among persons affected with alcoholic gastritis, cirrhosis of the liver, and nervous complaints due to chronic alcoholism. Although, therefore, it is possible that the abuse of stimulants may so diminish the natural resistance of the tissues as to favour the inception of cancer, as it undoubtedly does that of tubercle, we do not believe that it is in any way an important factor. Cloquet has attributed the prevalence of cancer of the stomach in certain parts of Normandy to the consumption of acid cider, while Brunon and Bebulet regard the frequent admixture of sea water with that local drink as the deleterious agent. Neither of these views, however, has been endorsed by the committee appointed to investigate the subject, which seems to have considered that heredity was the principal cause of the prevalence of the complaint.
Although indulgence in meat or alcohol does not appear to favour the inception of carcinoma, it is quite possible that the mischief may be due to the inordinate consumption of some other article of diet. A comparative study of the food of savage and civilised communities at once indicates that at least two common articles of diet are usually wanting among those who appear to be naturally exempt from malignant disease. The first of these is bread made with yeast, and the other beer. It is also a curious fact that among the poorest agricultural populations, where these two products of civilisation are rarely employed, carcinoma is supposed to be rare, while in those districts where one or other is taken in excess the complaint is exceptionally common.1 It is also interesting to observe that modern pathologists are inclined to regard the cell-enclosures met with in carcinoma as more closely allied to yeast than to protozoa, and should this identity be established it will certainly be advisable to ascertain whether all or only a portion of the fungus employed in the preparation of bread and beer is really killed in the process of manufacture.