Your Majesty, Your Royal Highnesses, Ladies and Gentlemen.
Few diseases have the power of inspiring fear to the same degree as cancer. However, who would be surprised at that? How many times is this affliction not synonymous with a long, painful and grievous illness, how many times is it not equivalent to incurable suffering? It is therefore natural that we should strive to throw light upon its nature; but the road to this discovery is both long and difficult. Cancer always, in fact, presents the investigator with a number of obscure and unsolved problems. Thus the cause of cancer has for a long time baffled the penetrating studies of the most tireless research workers. Fibiger was the first of these to succeed in lifting with a sure hand a corner of the veil which hid from us the etiology of the disease; the first also, to enable us to replace with precise and demonstrable theories the hypotheses with which we had had to content ourselves.
For example, it had been thought for a long time that a causal connection existed between cancer and a prolonged irritation of some sort, mechanical, thermal, chemical, radiant, etc.; this supposition was supported by the incidence, sometimes verified, of cancer as an occupational disease. Cancer occurring in radiologists, chimney sweepers, workers in the manufacture of chemical products, establish so many examples of cancerous infection that one might believe they were provoked by radioactive or chemical irritation. However, each time experiment was resorted to in an attempt to provoke cancer in animals by irritants of this nature, it failed, and the animals refused to contract the disease.
Others, with all the more reason, sought to find in cancer the work of microparasites, for true neoplastic epizootics were thought sometimes to have been established in the animal world. But research into the pathogenic agent, the «cancer bacillus», and the experiments attempting to inoculate the disease had remained fruitless. Cancer has been equally attributed to other parasites, and notably to the worm. But, just as the attempts to provoke cancer, whether by inoculation or by irritation remained unproductive, in the same way it proved impossible to demonstrate experimentally that the disease was attributable to worms. These authorities who continued to support this thesis were, moreover, frequently considered to be fantasts. Because of the failure of attempts to establish, by experiment, the accuracy of any theory, there was no clear idea concerning the cause of cancer, and such in general was the position of this question. Then it was, in 1913, that Fibiger discovered that cancer could be produced experimentally.
It is of the greatest interest to follow Fibiger along the laborious path of his research. The first idea of his discovery, which was to make his name celebrated the world over came to him in 1907: he recorded in three mice in his laboratory (originating from Dorpat), a tumour, unknown until that time in the stomach; in the centre of the neoplasm he noted the presence of a worm belonging to the family of Spiroptera.
Fibiger did not succeed at first in proving a relationship existing between the formation of the neoplasm and the worm. The attempts to provoke a cancer in healthy mice by making them ingest neoplastic tissue from diseased mice, and containing worms or eggs, failed completely. Fibiger then had the idea that perhaps this worm, like many others, underwent part of its evolution from an egg to an adult individual in another animal, which served as an intermediate host. After numerous and vain attempts to find again mice attacked by the tumours seen in 1907 – he unsuccessfully examined more than 1000 animals – Fibiger eventually discovered in a sugar refinery in Copenhagen mice who exhibited in considerable numbers the type of tumour he was seeking; in these tumours he found once again the worm he had observed in 1907. The factory was at this time infested with cockroaches, and Fibiger was then able to establish that the worm in its evolution used these cockroaches as intermediate hosts. The cockroaches ingested the excreta of the mice, and with them the eggs of the worm. These developed in the alimentary tract of the cockroaches into larvae, which, like the trichina, were distributed into the muscles of the insects where they become encapsulated. The cockroaches were in their turn eaten by the mice and in the stomach the larvae transformed into the adult form.
By feeding healthy mice with cockroaches containing the larvae of the spiroptera, Fibiger succeeded in producing cancerous growths in the stomachs of a large number of animals. It was therefore possible, for the first time, to change by experiment normal cells into cells having all the terrible properties of cancer. It was thus shown authoritatively not that cancer is always caused by a worm, but that it can be provoked by an external stimulus. For this reason alone the discovery was of incalculable importance.
But Fibiger’s discovery had a still greater significance. The possibility of experimentally producing cancer gave to the particular research into this illness an invaluable and badly needed method, lacking until this time, allowing the elucidation of some of the obscure points in the problem of cancer. Fibiger’s discovery also gave remarkable impetus to research. Whereas research had, in many respects, entered upon a period of stagnation, Fibiger’s discovery marked the beginning of a new era, of a new epoch in the history of cancer, to which the fruitful research made by him gave fresh vigour. From his discoveries we have continued to march forward and have gained valuable ideas as to the nature of this illness.
It is thus that Fibiger has been and will remain a pioneer in the difficult field of cancer research. «To my mind», says the famous English expert on cancer, Archibald Leitch, to name only one of the numerous critical commentators on Fibiger’s research, «Fibiger’s work has been the greatest contribution to experimental medicine in our generation. He has built into the growing structure of truth something outstanding, something immortal, quod non imber edax possit diruere.» It is for this immortal research work that Fibiger is today awarded the Nobel Prize for Medicine for 1926.
Johannes Fibiger, honoured colleague. You have used the skill of your mature years to search for the cause of cancer. Thanks to penetrating observation, to conscientious and indefatigable work, you have succeeded in giving us convincing facts in place of unauthenticated hypotheses. You have thus, in a field of singular importance, enriched with new knowledge the sphere of medical research. You have at the same time given to the study of cancer a method for resolving points which are still obscure. You have stimulated this study as few others have done; you have drawn to its structure new workers who build on your foundations. We may perhaps hope that the day will come when we shall understand the problem of cancer in its entirety. If, on that day, we look back along the hard path we have travelled, your name will shine among the greatest, and you will remain a pioneer and a forerunner. The Staff of Professors of the Caroline Institute has decided to award you the Nobel Prize for Medicine for 1926 for your share in the annals of medicine. In expressing the warm congratulations of the Institute, I have the great honour of inviting you to present yourself before the King to receive your prize from his hands.