LIVING VIRUS?

Evening Star, Issue 20989, 31 December 1931, Page 10

LIVING VIRUS?

CAUSE OF GANGER IMPORTANT RESEARCH The problem of cancer is being approached from so many different angles by so many different workers that there is always a danger of its details being magnified at the expense of the whole. That is why a book published by Drs W. K. Gye and W. J. Purdy, members of the scientific staff of the National Institute for Medical Research, is one of the most interesting that have over been written, and may very possibly prove to be one of • the most important, says the medical correspondent of the ‘ Daily Telegraph.’ For some years Dr Gye has been recognised as one of the most brilliant investigators at work in this country. In the present volume ho is chiefly concerned to establish a controversial point. But he has nevertheless been able, with his collaborator, to stand away, as it were, from his immediate preoccupation, and the result is as masterly and dispassionate a view of cancer as has been penned in recent literature. Cancer, as Drs Gye and Purdy remind us, has been known and_ described over since the dawn of medicine. Primitive races are afflicted with cancer, and so are lower animals, both domestic and wild. No habit of life, no dietetic peculiarity has been shown to affect susceptibility. Though it may arise in almost any tissue of the body, the cells which compose it always remain true to type and to the particular typo of cell in which it happens to originate. But these cells have a lawless and apparently indefinite power of growth, and should they become detached from the main tumor, have tho power of forming the nuclei of fresh secondary growths in other parts .of the body. Turning to research, there have been, as Drs Gye and Purdy remind us, three cardinal discoveries. German and Danish investigators were the first to show that cancer was of common occurrence in most vertebrate animals, and could be propagated artificially by moans of coll grafts. Fibiger, of Copenhagen, Jamagiwa and Itchikawa, of Japan, showed that it could be produced do novo by prolonging extrinsic irritation. And finally Peyton Rous, of the Rockefeller Institute, New York, showed that malignant tumours in fowls could be propagated by cell-free filtrates of these tumours to other fowls-. CELLULAR. It is upon this last discovery that Drs Gye and Purdy have based the greater part of the experimental work which is recorded in their volume. Before Rous’s work it was generally assumed that cancer, in its basic sense, was a strictly cellular disorder, but to some inherent chemical or biological change in the constitution of the cell or its nucleus. It was this that started it upon its lawless and independent course of multiplication; and it was only by some individual member of this outlaw group that cancer could be induced in a healthy animal or cause a secondary growth in its original host. But Rous’s work apparently upset this. In fowls, at any rate, he was able to induce growths with so small an injection as .001 c.c. of a filtrate, from which every cellular element had been eliminated. Although no microscopical verification was forthcoming, this filtrate behaved in a manner very strictly analogous to one containing a living organism. And it was because of this that the theory of a virus, or submicroscopical living agent of cancer was first promulgated.

For various reasons this theory has not yet obtained a full measure of scientific support. It has not yet been found possible, for instance, to induce growths by cell-free filtrates of mammalian cancor. And the variety of types of cancer, their specificity to the particular kind of animal in which they occur, has seeuned to involve the unlikely supposition of many kinds of cancer virus. The true malignancy of tho Rous timiours has also been doubted.

In face of tho evidence now adduced, however, by Drs Gyo and Purdy, this latter point can scarcely be maintained. ‘And it would seem difficult, in view of accumulating observations and their own very careful experiments, to resist the conclusion that in fowls, at any rate, cancer is indeed the result of a living organism. But if in fowls, why not in mammals, including human beings ? That is the question put By Dr Gye, and though the arguments against it are undoubtedly weighty* they are mostly based, as Dr Gyo pofoits out, on negative evidence. Probably the most cogent is „he difficulty, already referred to, of assuming a common virus able to produce malignant growths of such diversity and so strictly specific to their particular breed of animal hosts; and the almost equally difficult alternative of imagining a large number of different cancer viruses. ADDED “ SOMETHING.” This is a difficulty, however, that Drs Gye and Purdy have most ingeniously attacked. By a series of well-planned experiments they have demonstrated that the cell-free filtrate, which produces the Rous fowl tumours, consists of two parts, a living one or virus, that can bo destroyed by antiseptics, and another, probably derived from tho invaded cells themselves, that can be destroyed by heat. Lacking either, tiio filtrate is innocuous. But they have even gone further. To a filtrate deprived of its virus they added “ something ” diffused from a similar malignant growth in a rat. They then found that the filtrate again became active and produced in a healthy fowl tho typical original fowl tumour. If this is confirmed by other observers it will assuredly be one of the landmarks in cancer research, ;j - means that this “ something,” presumably a virus, can replace that responsible for the fowl tumour, although it comes from another species. Based upon this, and tho whole body of their work, Dr Gyo and his collaborator have definitely come, therefore, to tho conclusion that all cancer is caused by a common living virus acting in conjunction with another component, which is responsible for the peculiar intensely specific, cellular reaction characteristic of malignant growths. Neither can act alone, and the probability is, in the writers’ view, that the cancer virus is widespread, and of relatively low infestivity. How it invades tho body or meets tho requisite cell pre-condition that enables it to become active is not .vet known. But if the material brought forward by Drs Gye and Purdy triumphs over the tests that will assuredly bo applied to it, an advance will have been made in our knowledge of cancer that it would bo difficult to exaggerate.