Cancer in man exists all over the globe, but in different degrees of frequency, according to varying conditions of life, as we shall presently see. Malignant growths occur also in animals and fishes, though also with greatly varying frequency under different conditions; but there are few real tumors in reptiles or amphibians. Tumors are also occasionally found in vegetable organisms, presenting increased growth and proliferation of cells, arising from adventitious, or abnormally evolving buds, as also from parasitic and other external irritants. While these vegetable tumors are very interesting and in a measure instructive, in regard to the peculiarities of cell growth which they exhibit, they bear, of course, no relation to cancer in the animal kingdom, although some have endeavored to argue otherwise. There is, however, a certain suggestion of analogy to be found in the observation made by one writer, that “the origin of buds, as well as their subsequent development, is chiefly determined by the conditions of nutrition. Wherever there is an excess of nutritive material, capable of being utilized for growth by the cells of the part, there buds may arise”; we shall see later that the same thought applies to cancer in man and animals, when we come to the consideration of the relation of overindulgence along certain lines of eating and drinking to cancer.

Cancer has well been styled a disease of modern civilization, like tuberculosis, although of quite a different nature. Interesting studies have been made in regard to the increased death rate from the former in England, coincident with a diminished mortality of the latter, in accordance with nutritional changes which have taken place in certain populations: and in the first lecture I mentioned that in the United States the mortality from tuberculosis had fallen 25 per cent. between 1900 and 1912 while, as we shall see later, the mortality from cancer has certainly risen.

Williams, who quotes very largely from the accurate statistics which have long been carefully recorded in England, says that “while tubercle has declined with great rapidity, cancer has increased at a still faster rate, and these inversely related changes are still in active progress. In illustration of these remarks it may be mentioned that during the last half of the nineteenth century, the cancer mortality for England tripled: while, during the same period the tubercle death rate declined to the extent of nearly one-half. Unless some great change in the national habits takes place, of which there is at the present no well marked indication, cancer will ere long claim more victims than phthisis, as is already the case in many localities—e. g., Hampstead, Clifton, Bath, etc.” He further says, “I regard this decline in the presence of tuberculous diseases as the direct outcome of the better food and improved hygienic conditions, for which we are indebted to our increased national prosperity: and I shall endeavor to show that conditions of this kind, by their action in another direction, are also mainly responsible for the augmented cancer mortality.” We shall see later that cancer has asserted itself where modern civilization has augmented the opportunities of overindulgence along many lines of eating and drinking: for while advancing scientific knowledge has undoubtedly diminished mortality in general, and has added to the average length of life, the various factors included in our modern mode of living have also with certainty increased morbidity along such lines as neurotic and vascular disorders, tumors, etc.

All statistics from various localities show that cancer has certainly increased in frequency very greatly of late years, and though some have attempted to claim that this increase is only apparent, and is due to greater accuracy of diagnosis, and the prolonging of more lives to an age when cancer is more common, there is no doubt in the minds of those who have studied the figures that the increase is certainly very real; and unless there be found some way to check its production, the death rate at the end of the century will be appalling.

It is quite impossible here even to give a comprehensive idea of the immense amount of work which has been given to the study of the statistics of cancer in various parts of the world, as collected in the remarkable works of Roger Williams and Jacob Wolff, but brief mention must be made of some of the items observed and recorded in order to properly understand our subject. Williams in particular has analyzed the recorded facts in an interesting and convincing manner, and shown again and again in connection with the figures from different countries, sections, and cities, that the occurrence of cancer bears a striking relation to the condition of the people in reference to their material prosperity; namely, that the well-to-do, who can overindulge in many ways are vastly more subject to cancer than those in the poorer walks of life; also that aborigines in the wilder parts of the world are either almost exempt from cancer, or suffer from it to a very much less degree than civilized foreigners who come to their lands. This is also shown in a very striking manner by Wolff, and I present here a table which he gives in regard to the progress of cancer in a single country, Australia, among the native born and foreigners.

He remarks, “We see from this comparison in what a great degree the death rate from cancer has increased in foreigners as compared to the native born, in whom the disease has remained about stationary, when the increase in population is considered.” Another writer remarks that when native Australians mingle with foreigners as servants or employés, and adopt their diet and customs, cancer occurs more frequently in them. Much the same has been reported in regard to other peoples and nationalities, and later we will consider the influences of urban life on the production of cancer.

In New Zealand, according to Hislop and Fenwick, where the general death rate is the lowest in the world, cancer is on the increase, as civilization advances. In the great majority of cases the alimentary canal is the seat of invasion, even in women: all the patients studied were hearty eaters, taking also very much strong tea many times daily.

The Polynesians and Melanesians seem to be peculiarly exempt from cancer. Sir William McGregor, although he had operated several times on whites in the Fiji Islands, never remembers operating on a Polynesian or Melanesian, who are practically vegetarians. He never saw a case in British Guinea in 9½ years, and then saw an encephaloid cancer of the tibia in a Papuan, who for 7 or 8 years had lived practically a European life, eating canned Australian meat daily.

In regard to Africa, Williams quotes Dr. Madden of Cairo, who says, “The consensus of opinion among medical men in Egypt is, that cancer is never found, either in male or female, among the black races of that country. These include the Berberines and the Sudanese, who are all Mussulmans, and live almost entirely upon vegetable diet.” Of 19,529 deaths among natives of Cairo during 1891, only 19 were due to cancer (females 10, males 9) or 1 in 1028. In England during the same year the proportion of cancer deaths to total deaths was 1 in 29. In the Islands of Lagos, on the West Coast of Africa, Dr. Johnson, in 14 years’ practice there saw 5 cases of cancer in natives all of whom lived as Europeans. In southern Africa, “among the Boers and Europeans, who are large flesh eaters, malignant tumors are common: but among the natives, who are mainly vegetarians, these tumors are so rare as to be almost unknown.”

Renner reports interestingly in regard to cancer among the descendants of liberated Africans or Creoles, in Sierra Leone, Africa. During 30 years, from 1870 to 1900, there were but 20 cases recorded as malignant disease among 22,453 admitted to the Colonial Hospital: in the next ten years there were 26 among a total of 10,163, a slow but steady gain in cancer incidence, with the advancing influence of the white man. He says that while the aborigines eat no meat, the “Creoles” eat much meat; the teeth of the latter are beginning to decay, like those of the whites, which is attributed to the sweets introduced by the latter. Every case of cancer recorded has been in a Creole, living like a European, and not a single case among the aborigines.

Much the same freedom from cancer has been noted in regard to negroes when first brought to the United States in slavery, when their food and mode of life was simple: but since emancipation and in proportion as they have mingled with whites and eaten their food, with their own natural tendency to gluttony and laziness, cancer has increased among them, although their death rate from malignant disease is still much less than that of whites.

In India all writers agree that cancer is rare among the inhabitants of warmer country districts, where they live largely on rice or millet, with a little milk and butter, and vegetables: they eat meat rarely, the immense majority of the people live a rural life, depending upon agriculture for their sustenance.

Investigations of late years, however, might seem to indicate that cancer is more prevalent in India than previously supposed, but its incidence still bears no real relation to that in many other countries, and an analysis of some recent reports explains in an interesting and curious manner the reasons for the diversity of opinion as to the actual frequency of the disease.

Thus, Benratt collected a total of 1700 cases only from 5 years’ statistics of 15 Mission Hospitals and 34 Government Hospitals, representing, of course, many million inhabitants, whereas in New York City, according to the weekly Bulletin of the Board of Health, there were 2193 deaths from cancer in the last six months, a striking illustration of the rarity of cancer in India. Moreover of these 1700 cases, over 1200 were about the mouth, a very large share of these arising from the very common habit of chewing betel, which contains also much calcium, which latter is one of the salts incriminated in the causation of cancer. Sandwith attempts to show that cancer is prevalent in India, but refers to only 2000 cases reported in the hospitals there, in three years, also among many millions of people, and he refers likewise to the betel chewing cancer, and the “kangri burn” on the abdomen of men, from the charcoal furnace worn for warmth: these peculiar local disorders vitiate any deductions which could be drawn from such statistics.

In China, according to a recent writer, “cancer is comparatively uncommon in those parts where the bulk of the people live on an almost exclusively vegetarian diet, being too poor to purchase any of the various flesh foods, which are there used for culinary purposes.” But in places where cancer is said to be more prevalent, the reporter adds, “All Chinamen there eat fish and pork at morning and evening meals: fowls and ducks are always on the table of all but the most humble of the coolie class.”

In regard to the occurrence of cancer in the Far East, however, some of the modern investigators, such as Bashford, have endeavored to overturn the generally accepted view as to its infrequency, but I do not feel that the evidence presented can at all weigh against the unprejudiced opinion of most capable medical men who have long lived and practiced in those regions, some of whom as medical missionaries have had most intimate contact and acquaintance with the natives. Only very recently a medical missionary, who has long been connected with the medical college and hospital in Beirut, Syria, told me that cancer was practically unknown among the thousands of patients who flock there from all over the Near East, he adding that they were all largely vegetarians.

During a rather extensive trip through the Far East I was unable to see or even hear of any cancer, although I met a large number of medical men, and made diligent inquiry regarding the same. As I wished to verify my views in regard to the rarity of the occurrence of cancer among those who lived on rice or other vegetarian diet, I visited very many civil, military, and mission hospitals, with a total of many thousands of patients, and ministering to many millions of population; in Japan, Korea, China, the Philippines, India, Siam, and Egypt, I met the same response, that cancer was rarely seen among those vegetarian natives.

Brazil is credited with having the lowest cancer record of any portion of the western hemisphere, especially among the natives in the Equatorial regions, while in the Argentine Republic, where meat is known to be largely consumed, cancer is fairly common. From many parts of the world there come reports of the relative infrequency or even absence of cancer among simple living natives, one writer in regard to the West Indies stating “Even those cases which I have witnessed in this class of people have been among the better orders of them, whose habits of living assimilated to those of Europeans.”

England and Wales present the most satisfactory field for the study of the progress of cancer, as the national vital statistics have been well kept since 1840; even at that time under the able direction of William Farr they had already acquired a well-deserved reputation for reliability, as Williams remarks, from whom I shall freely quote.

In that year, 1840, there died of malignant disease in England and Wales 1 in 5,646 of the total population, 1 in 129 of the total mortality, or 117 per million living. In 1905, the deaths, due to this cause were 1 in 1,131 of the total population, 1 in 17 of the total mortality, or 885 per million living: thus, while the population had only a little more than doubled, the cancer death rate per million living had increased five fold. Dr. Williams answers by figures and tables the several objections which have been raised in regard to the actual increased mortality from cancer, as it has been repeatedly claimed that the increase is only apparent and not real; thus it has been asserted that it is due—1. To mere increase of population: 2. To the average age of the population having advanced: and 3. To improved diagnosis and more careful death certification. Time does not admit a full presentation of his statistical refutation of these claims, to which he devotes some pages very convincingly, but it can be safely accepted that for some as yet unknown reason, cancer has made strides in England which are truly alarming.

Williams has also made some most interesting studies in regard to the increase of cancer in connection with changed conditions of life, and from his analysis of statistics, he very clearly shows that the spread of the disease has closely followed urbanization, and the rapid increase in material prosperity of recent years: in England where 80 per cent. of the population are now town dwellers, this tendency to collect in cities and towns has gone farther than in any other community. He recognizes that any far-reaching, environmental change of some duration is probably potent in disturbing the stability of the constituents of living bodies, and the sudden change from poverty to riches and plenty is conducive to the development of cancer: allusion has already been made to the inverse relation of deaths from cancer and tuberculosis, the latter diminishing with improved material conditions, while the former increases as wealth and indolence increase.

He shows this by statistics from various localities, and by data from towns in different countries he makes it pretty clear that “Cancer mortality is lowest where the conditions of life are hardest, the surroundings the most squalid, the density of population greatest, where the tubercle mortality is highest, the general and infantile mortality greatest, and where sanitation is least perfect—in short, among the poor of the industrial class in our great towns: whereas among the wealthy and well-to-do, where the standard of health is at its best and life is easiest, and where all the conditions of life are just the reverse of the foregoing, there the cancer mortality is highest.”

While this is a pretty strong statement and many exceptions could undoubtedly be found, careful investigation will show it to be true in the main; for it must be remembered that even among the poorer classes gluttony, especially in regard to proteids, is not at all uncommon, and indolence, with impeded metabolism, is not at all unusual. Dr. Latham found that the mortality from cancer in England, from 1881–1890, was more than twice as great among well-to-do men having no specific occupation, as among occupied males in general, the respective mortality ratios being 96 for the former and only 44 for the latter. Sir William Banks confirms the steady increase in cancer very strongly, which he attributes to richer and more abundant food, of which males eat more than females, and consequently cancer is increasing proportionately more among men, as all statistics show.

Switzerland is reported to have the highest death rate from cancer of any country, it having augmented from 114 per 100,000 living in 1889, to 132 in 1898. There again the cancer mortality varies greatly in the different sections or cantons: thus, in wealthy Lucerne it is 204 per 100,000 living, and only 36 in poverty stricken Valais. In the city of Geneva it is 177 per 100,000 living.

Denmark, next to Switzerland, is reputed to have the highest cancer death rate of any country in Europe, viz.: 130 per 100,000 living in 1900. But here the statistics are only from the towns, which comprise but a quarter of the whole population: the per capita wealth is said to be higher there than any other country in Europe except France.

France shows a high cancer mortality, with a constantly increasing death rate; and, next to England, France is the richest country in Europe, and wealth is much more widely diffused: the French workers own nearly 8 times, per capita, more than those in England. In Paris the cancer death rate has increased as follows, for each 100,000 living, in 1865, 84; in 1870, 91; in 1880, 94; in 1890, 108; in 1900, 120.

Italy, a comparatively poor country, shows a low cancer mortality, but even here it is increasing from 20 per 100,000 living in 1880, to 52 in 1899, and 58 in 1905. The consumption of meat is there the smallest in any European nation, namely 23 pounds per capita in 1895. In the chief towns the rate of death from cancer is high: thus for each 100,000 living, in Florence 137, Ravenna 120, Venice 103, Milan 101, and Rome 77.

Time does not permit a wider survey of the field of distribution of cancer, as presented so remarkably from official statistics by Williams, and Wolff; but in connection with the high percentages of deaths above quoted among the richer classes it may be interesting to mention some of the lowest records. Thus, in the poor country of Kerry, Ireland, it was 27 per 100,000 living, in the province of Dalmaltia 19, in the Shetland Islands 16, in Servia 8 (from 1895 to 1904), and in Ceylon in 1903 the mortality from cancer was about 6 for each 100,000 living.

The United States, unfortunately, has not kept the vital statistics of the country in years past with anything like the fullness and accuracy which has obtained in England, nor even at the present time is it possible to learn definitely the frequency and increase of cancer in every locality. But all the statistics which have been gathered show unequivocally that the disease has steadily increased in a manner which is alarming. Analyzing the recorded deaths from cancer in thirty-one cities, and the percentage of increase in four years, one writer estimates that, if the same increase is continued, by the end of the century there will be a death rate, approximately, of 1000 in every 100,000 inhabitants, or one in every hundred.

In a recent Bulletin of the Board of Health of New York City the following statements are made in regard to the mortality from cancer in 1913: “The statistics of our seven largest cities recently tabulated, show that the cancer death rate was the highest on record. For New York City the rate was 82 per 100,000 of the population, against an average of 79, for the last five years: for Boston 118 against an average of 110: for Pittsburgh 79, against an average of 70: for Baltimore 105, against an average of 94: for Chicago 86, against an average of 81: for Philadelphia 95, against an average of 88: for St. Louis 95, against an average of 85.” This average increase of almost 8 per cent. of deaths from cancer in the combined population of these seven cities, during the last five years is certainly an alarming fact, and cannot be explained on the ground of greater accuracy of diagnosis: for it is not to be presumed that there has been such great improvement along diagnostic lines during the single year 1913.

It is difficult to state the exact prevalence of cancer in the entire United States, as the “registration areas” include only about two-thirds of the total population: much can be learned, however, from the annual volumes published since 1900. According to these Mortality Statistics of the United States, the deaths from cancer and other malignant tumors per 100,000 population were as follows: in 1900, 63, in 1904, 70.2, in 1909, 73.8; and in 1912 there were 46,531 deaths from cancer, or 77 per 100,000 population, an increase in the death rate from this disease of almost 25 per cent. since 1900; while, as before stated the tuberculosis mortality had fallen a little over 25 per cent. in the same period.

As in other countries, which might also be expected from the statements already made, the disease varies in frequency in different localities and communities. Thus, cancer is stated to be much more prevalent in the northern than in the southern states, and as already stated, the negroes are much less subject to the disease than whites, especially when they are living their own natural home life; but when they come to the cities, as waiters, etc., in hotels, their cancer death rate increases. But even in New York City in 1912 the deaths from cancer in negroes was 1 in 32.2 total deaths, against 1 in 17.7 in whites; the mass of negroes here, of course, live plainly and work hard. The North American Indians also are believed to be almost exempt from cancer in their primitive savage condition, but as they have come under the influence of civilization they are more affected. It has also been noted by several observers that immigrants and their descendants present a very much higher mortality from malignant diseases than prevails in their native countries; from these and other considerations Williams suggests that abrupt change of environment may also be a factor in the causation of this disease.

We have thus seen while cancer is very widely distributed over the globe it is present in varying degrees of severity in different localities, and careful analysis shows that the disease affects different classes of persons with unlike severity. All these statistical studies and observations serve to confirm the statement made earlier that cancer is a disease of so-called civilization, and that it has increased in proportion as human beings have come under the influence of wealth, and consequent luxury and overindulgence, with bodily inactivity; all these elements lead to a disturbed metabolism, which as we shall see later, is, at least, a contributing cause to the deviation from normal of some of the cellular elements of the body. It also appears that some of these metabolic shortcomings have to do with a disturbed nitrogenous balance, which is due to the constantly increased consumption of meat. In 1909 the meat consumption in the United States had reached the high figure of 172 pounds per capita, as I learned recently from Washington, a far greater amount than in England, 130 pounds, as already stated; and with this steady increase in the use of nitrogenous food cancer has also increased by leaps and bounds in both countries.