REVIEWS 563 



The elaborate experiments on mice have been continued ; they have for their 

 aim "the modification or control of the growth of cancer." The study of the 

 constancy and variability of tumour cells has also been continued because it may 

 throw light on the association of " chronic irritation " with some forms of cancer, 

 and objection is taken to the haphazard hypotheses which have appeared in both 

 lay and medical journals. The alteration of carcinoma into sarcoma has again 

 been investigated, as well as the nature of the resistance to cancer which can be 

 induced in animals. The fact is mentioned that cancer cells retain their biological 

 properties when transplanted into fertilised hens' eggs. Abderhalden's test has 

 also been reinvestigated, and a note of warning is issued as to its reliability. 



The statistical portion of the Report is occupied with the discussion whether 

 there is a real general increase of cancer and with the question of the possible 

 existence of " cancer houses and areas." Dr. Bashford concludes that the latter 

 are a myth, a conclusion which has been widely repeated in the lay papers. 



There is no doubt that, as in former years, the Imperial Cancer Research Fund 

 has done an immense amount of work ; but one cannot help feeling that Dr. 

 Bashford and his colleagues are trying to run before they can walk. It is all 

 very well to transplant masses of cells from one animal to another and then post 

 mortem to cut sections of them, for this shows some phenomena interesting to 

 pathological anatomy. But are we justified in saying from this that we are 

 authorities on the biology of tumour cells ? We might as well assert that the 

 political economy of Siam may explain why the individual Siamese have black 

 skins. The incessant transplantation of masses of mouse tumour is undoubtedly 

 of importance, but what is required is to ascertain the life-history of the individual 

 cells and what prompts that life-history. In what way is a cancer cell different 

 from a normal cell ; what makes it a cancer cell ; what makes it divide so rapidly ; 

 what makes it infiltrate and gives it the power of growing in the abnormal 

 surroundings of other tissues — these are questions which do not appear to be 

 discussed. It is difficult to believe that the mere transplantation of mouse tumour 

 masses can possibly answer them, and there is a danger of the workers falling 

 into a groove that can only lead them into a vicious circle. It is to be hoped that 

 the Imperial Fund will investigate the individual cell more, especially with the 

 object of finding the immediate cause of both its normal and malignant prolifera- 

 tion. What makes a cell divide seems to be a fundamental question. 



The efforts made to elucidate the resistance to animal tumour growth are 

 excellent, but they seem rather to be beginning at the end of the problem. It is 

 true that questions of heredity have been investigated, but the predisposing causes 

 of the disease are hardly touched upon. We are informed that " chronic irrita- 

 tion " predisposes certain tissues to cancer, but the expression itself is not defined. 

 The term "irritation" is a clinical one ; what is the effect of it on a single cell? 

 What is the difference between the effects of chemical and mechanical irritation 

 on the single cell ? The probable causes of benign tumours, which are a predis- 

 position to cancer, are not mentioned. 



The Imperial Fund has never advanced a definite working hypothesis, but it 

 has stated its belief that cancer is not an infective disease caused by a foreign 

 organism. No explanation is offered as to why an overgrowth of certain cells of 

 the animal economy which were at one time normal ones should kill their host and 

 thereby kill themselves — a form of racial suicide which does not help in the repro- 

 duction of species and which seems to have no parallels in nature. There is a 

 vague hint that the cause of cancer is of some obscure intracellular nature, but 

 this is not borne out by research into industrial cancer, which, by the way, is not 



