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Bilharzia for the bladder, the tubercle bacillus where epithelioma develops in an old lupus scar, or Treponema pallidum, as in the association of keratosis linguæ with epithelioma of the tongue. The irritant may be a larger parasite. Borrel has recorded the association of cancer with nematodes and cestodes, and we have observed a case of carcinoma of the small intestine in a mouse at the site of attachment of a tape-worm. The irritants cited can readily be augmented by the enumeration of many others having nothing in common, and they can have only a mediate relation to the causation of the disease. This is a conclusion we have expressed already, and it will be reverted to again in discussing the occurrence of cancer in animals, without studying which it would be very unwise to express any opinion on the significance of the association of chronic irritation with the development of cancer in man.

The study of all the circumstances associated with the sporadic occurrence of cancer must remain indispensable so long as we are unable to test the relative importance of each by other than statistical methods. The true importance of some of the circumstances which have been defined as having a mediate relation to the development of cancer, can only be cleared up after its nature has been ascertained, and purely statistical investigations will remain more or less empirical until this end is attained. The statistical investigation of infective diseases was pursued advantageously before the development of bacteriology directly demonstrated the causes of many of them. That demonstration placed old problems in their true perspective, e. g. the geographical distribution of infective diseases, their epidemic and endemic occurrence, the relation between variations in the incidence of infective diseases, and, e. g., watersupply, density of population, rainfall, ground-water, or season. In the case of cancer those who have a serious interest in statistics have not yet advanced from the state of empiricism in which the student of the infective diseases compiled statistics in the days before Pasteur and Koch. It is unjust to minimise the value of the accurate statistics based on the available data, for in our ignorance we do not know that the statistical method has reached its limitations; but only that it is still of the greatest assistance in helping us to define the objective of our experimental studies.

The increased number of deaths recorded from cancer, its apparent greater frequency in some geographical areas (whether large or small) than others, the assumed importance or unimportance of the influences of race, diet, soil, climate, are all problems of much less importance than, e. g., the established fact that cancer increases in frequency as age

advances in man and animals, and, the infective or non-infective nature of cancer. Still it may not be forgotten, it was impossible for statistics to supply the proofs of the causes of diseases now known to depend on infective organisms, and it is in all probability as much without the province of statistics to supply the answer to these questions, as it is for them to yield a reply to the still more direct question-What is the cause of cancer?

The occurrence of cancer in association with chronic irritation has long been recognised, and has led to conceptions of the nature of the disease more or less out of accord with the hypothesis of a congenital origin as a general explanation of all forms of cancer. The facts recorded above seem to show that the different forms of irritation, although they have in themselves nothing in common, are of more moment than the sites to which they are applied. If the hypothesis of a congenital origin is to hold good for the various instances mentioned in the preceding pages, then it becomes necessary to postulate further a uniform and abundant distribution of "embryonic rests" over the body, or to assume a different distribution of "embryonic rests" in Europeans and native races, coinciding with the points they respectively select for the indulgence of various practices involving the application of peculiar irritations. The facts directly refute such a view of the congenital origin of those forms of cancer to which reference has been made above, as developing in consequence of such native customs as, e. g., wearing the Kangri or chewing betel-nut. The same remarks apply also to other better known forms of cancer associated with chronic irritation, e. g., chimney-sweeps-cancer, and to still less known forms, e. g., brandcancer and "horn-core" in cattle. The difference in the organ incidence of cancer between Europeans and the natives of Kashmir or India and Ceylon is that in Kashmir the abdominal wall is irritated by the Kangri, and the buccal mucous membrane of women in Ceylon and India generally, by chewing betel-nut-it is not in all probability a different. distribution of hypothetical "embryonic rests" from that obtaining in Europeans. To these observations and inductions we are now able to add others drawn directly from experiments on animals, and later on in this Report Dr. Haaland will describe the experimental development of sarcomata in mice, under circumstances which appear to throw much light on the reasons why cancer develops in associotion with continuous or intermittent efforts at repair and regeneration. Although at the present time it is necessary to write with great reserve in directly applying the results of experiments to the aetiology of cancer in man, nevertheless their bearing on the mediate causative relation obtaining

between the chronic irritants cited above and the onset of cancer is one of the most suggestive results yet attained.

The advance made by experimental investigations has enabled us to follow in detail the development of malignant connective tissue new growths during the artificial propagation of malignant epithelial new growths; but we have still much to learn of the nature of the process, and until we are able to start cancerous proliferation in any tissue at will, we shall remain in this same unfavourable position for determining the true importance of many circumstances, which at the same time it is unjustifiable to ignore. Nevertheless the study of the ethnological distribution of cancer cannot be divorced from the comparative and experimental investigations without grave danger of fundamental fallacies. The apparent though temporary specialisation exemplified in the succeeding papers in this report is necessary before conceptions unifying divergent observations can be evolved.

LITERATURE.

ASCHOFF.-Bericht über Krebs und Malaria in den englischen Kolonien. (Verhandlung des Komites für Krebsforschung, Heft 1, 1900-1902.)

BAELZ.-Ueber Vorkommen des Carcinoms in Japan. (Ibidem.)

BASHFORD & MURRAY.-The Statistical Investigation of Cancer. Scientific Reports of the Imperial Cancer Research Fund, No. 2, pt. 1 (1905). (Taylor & Francis, Fleet Street, London.)

BASHFORD.-Real and Apparent Differences in the Incidence of Cancer (Transactions of the Epidemiological Society of London, New Series, vol. xxvi. 1906-07.)

NEVE. Decade of Tumour Surgery in Kashmir Mission Hospital (Indian Medical Gazette, 1902).

PRINZING.- Medizinische Statistik. (Fischer, Jena, 1906.),

WEINBERG und GASTPAR.-Die bösartigen Neubildungen in Stuttgart, von 1873
bis 1902. (Zeitschrift für Krebsforschung, Band ii. Heft 3, 1904.)
WEINBERG.-Thesen für ätiologische Statistik des Krebses. (Münchener medizinische
Wochenschrift, No. 50, 1905.)

WEINBERG.-Bericht. Sitzung der Delegierten der Landeskomitees für Krebsforschung. (Ibidem.)

Annual Reports of the Registrar-General of births, deaths and marriages in England and Wales. Wyman & Sons, Fetter Lane, London.

Annual Report of the Central Sanitary Bureau of the Home Department of the Imperial Japanese Government. Tokyo (published also in English). Correspondence relating to Cancer Research (Colonies). Wyman & Sons, Fetter Lane, London. (Blue books and White papers, 1905-08.)

Bericht über den vom Komitee für Krebsforschung am 15 Oktober 1900 erhobene
Sammelforschung. (Fischer, Jena, 1902.)

[For other references to papers from the Laboratory of the Imperial Cancer
Research Fund, see complete Bibliography in Appendix.]

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ON THE OCCURRENCE OF NEW GROWTHS AMONG
THE NATIVES OF BRITISH NEW GUINEA.

By C. G. SELIGMANN, M.D., M.R.C.P.

THE observations recorded in this paper were made during eleven months
of the year 1904 spent in work in British New Guinea and the islands
of its dependent archipelagos as a member of the Daniels Ethnographical
Expedition. During this time pathological conditions were constantly
sought out and, owing to my being able to successfully treat some of the

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FIG. 1.-The area visited extends coastwise from Cape Possession to the Kempwelch
River in the Central Division, Inland the valley of the St. Joseph River,
and at the S.E. extremity of the Possession the Trobriands and their
dependent Islands.

cases brought to me, a very considerable number of sick people presented
themselves for advice.

New Guinea is a country so little known that it is everywhere but

just emerging from the Stone Age: its inhabitants over large areas cannot count beyond five, while it is so uncontaminated by white influence that the exanthemata, with the possible exception of German measles, are unknown, and there are large areas into which venereal diseases have not yet been introduced.

The incidence of new growths among such primitive isolated and uncontaminated folk as these Papuasians* cannot but be of extreme interest, even if the conclusions to be drawn from the knowledge at present available are scanty.

Our knowledge of the occurrence of new growths among the darkskinned races of the Pacific is too slight to make any general comparison possible; but since the conditions prevalent in Australia and the Bismarck Archipelago will be briefly alluded to a few pages hence, it seems well at the beginning of the subject to emphasise the necessity of keeping clearly in mind the difference between race and colour. This is especially important in such an area of racial mixture as the Western Pacific.

Thus, to take an example peculiarly apt to the matter under discussion, the Australian and true or Western Papuan, although of about the same colour, vary considerably as to their capacity for the production of hypertrophied scars; and this in spite of the fact that both races produce scars intentionally. Further, while I have not seen enough Australians to be confident on this point, I am inclined to believe that these hypertrophied scars maintain their prominence for a much shorter time among Papuans than in Australians. As a matter of fact, in spite of the very marked tendency towards hypertrophy of cicatricial tissue in Australians, true tumours among them seem to be even rarer than among Papuans, and although I have made inquiries, I have never heard of a mass suggesting an ovarian tumour or a uterine fibroid occurring in a pure-blooded Australian. Dr. W. E. Roth tells me, moreover, that in all his experience among the natives of North-West Central Queensland he has seen no case which in his opinion was a new growth; while Professor Stirling, in his report of the work of the Horn Expedition to Central Australia, mentions but one case of new growth-an epithelioma of the foot in a native at Oodnadatta, who was about to submit to amputation t.

* The term Papuasian is used for any native of New Guinea and the neighbouring islands born of parents themselves natives of New Guinea or its archipelagos.

+ Report of the Work of the Horn Scientific Expedition to Central Queensland, Part IV. p. 129.

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