March 9, 1922] 



NATURE 



311 



Cancer Research. 



By Dr. J. A. Murray. 



"1"^ URING the last twenty or thirty years the above 

 J_y title has been very frequently the text for 

 reviews, summaries and editorial articles, and might 

 in other circumstances be regarded as covering an 

 over-written subject. The wide interest taken in 

 > ancerous diseases — an interest stimulated by the 

 apparently increasing toll of this malady which the 

 mortality figures of the Registrar-General reveal — 

 suggests that the editorial request for a further article 

 on the same theme should not be neglected. Recently 

 the general Press has contained the announcement of 

 Lord Atholstan's offer under certain conditions of a 

 prize of 22,000/. for the discovery of a medical cure 

 for cancer, whilst this has been followed by Sir William 

 Veno's prize of 10,000/. The final form in which these 

 sums will be applied to the stimulation, and perhaps 

 the subvention, of cancer research has probably not 

 yet been definitely decided, but both gifts can be 

 looked upon as concrete examples of the importance 

 which men attach to a solution of the problem of 

 cancer. 



At the present time we have in this country two 

 important and outstanding diseases, namely, cancer 

 and tubercle, both of which are great destroyers of 

 human life. The latter is certainly the more important 

 in an economic and social sense for it attacks people 

 at a much earlier age, but nevertheless it does not 

 seem to have the same hold as cancer on the imagina- 

 tion of the public. It would almost seem as if the 

 spes phthisica, the illusory hope of recovery often 

 entertained by the almost moribund consumptive, had 

 spread from the victim to his fellow-man. The prime 

 cause of tuberculosis has been known for forty years, 

 yet treatment is still very unsatisfactory ; in cancer the 

 cause is still unknown, and a wider field for investiga- 

 tion is presented, as well as one offering the attraction 

 of the unknown. 



Physicians and surgeons are not alone in entertain- 

 ing the interest thus awakened, but share it with a 

 wider army of pathologists, physiologists and biologists, 

 who may regard cancer as a perverted form of growth 

 perhaps induced by an aberrant type of metabolism. 

 If we restrict our survey to the period of the war and 

 the following years, we find that although research was 

 greatly curtailed, especially in Europe, it did not cease 

 entirely ; since the war, work has been resumed and 

 certain progress made. To-day, work is being done 

 even in impoverished Austria, and from Japan in the 

 East to the United States in the West, from Denmark 

 to the Argentine Republic. Investigation into the 

 nature of cancer is almost as widespread geographically 

 as the disease itself. 



It is at no time easy to formulate a working 

 hypothesis for attacking a biological problem, and it 

 is especially difficult in the case of the ill-defined one 

 we are considering ; but if the attempt be made 

 to analyse the different lines of inquiry adopted, 

 this might profitably be done by arranging them 

 according to their bearing upon the theory that 

 cancer is caused by an extraneous parasite. The 

 parasitic theory has been in the field for many years, 



NO. 2732, VOL. 109] 



but from the opening of the present century' it did not 

 claim so many adherents until about ten years ago, 

 when its advocates had their view strengthened by 

 the discovery of a peculiar sarcoma in fowls which 

 could be transmitted by a porcelain candle filtrate, and 

 presumably contained one of the filterable viruses. 

 The exact relation of this chicken sarcoma to the true 

 neoplasms is still a matter of uncertainty, but the 

 failure to repeat this experiment with tumours from 

 other animals leads one to suppose that their nature 

 is essentially different. A similar comment applies to 

 the infective venereal tumour of dogs, a sarcoma-like 

 growth transmitted by coitus, especially amongst bull- 

 dogs. Here, again, it is no easy matter to define the 

 relationship with the infective granulomata on one 

 hand, or with the true neoplasmata on the other. 



A great many of the opponents of the parasitic 

 theory of cancer believe in the efficiency of " chronic 

 irritation " as an actual inducer of the cancerous 

 transformation of a tissue. By chronic irritation they 

 usually mean a prolonged succession of chemical or 

 physical insults to a group of cells, these insults being 

 of a degree which does not destroy the vitality of the 

 cells but serves to excite their powers of growth and 

 reproduction. That cancerous disease may supervene 

 in tissues maltreated in this way is shown in a wide 

 variety of cases, of which there may be cited chimney- 

 sweeps' cancer, " kangri " cancer, the cancer of X-ray 

 workers, and the cancer developing at the site of a 

 long-standing ulceration. 



All these instances lead directly to the attempt to 

 produce cancer experimentally, but it is only within 

 the last few years that any measure of success has 

 attended the experiments. The production of cancer 

 has been most successful in rabbits and mice in which 

 a small skin area has been painted for a period of six 

 to twelve months with coal tar. About half the animals 

 thus treated show tumour growth at the treated site, 

 and the method promises to be exceedingly useful for 

 studying the conditions affecting tumour origin. 

 Another method of producing cancer experimentally 

 is less straightforward than the preceding, but about 

 equally efficacious. In this a chemical or physical 

 agent is not applied but the irritation produced by 

 the presence of a gross parasite is employed. The 

 artificial infection of rats by a species of nematode, 

 Gongylonema neoplastica, leads to the overgrowth of 

 the squamous portion of the stomach and in a fair 

 percentage of cases to the development of cancer. 

 Sarcoma of the liver of rats can also be produced with 

 ease by the simple expedient of infecting the animal 

 with ova of the cat tapeworm. Taenia crassicollis. All 

 three methods seem likely to further our knowledge of 

 the etiology of the disease. 



The search for the cause of cancer in a developmental 

 (embryonic) abnormality does not appear now to 

 command many followers ; it is at best a very fatalistic 

 line of thought, and discouraging to all but the most 

 robust-minded. 



Starting from an already established tumour, much 

 work has been done upon observing the characters of 



