The Parasitic Theory of Cancer

CANCER. 15I I occupations, cancer houses, and many others can only be settled after statistical and other investigations have be'en made and checked and cross-checked, controlled and re- controlled by each other.Such investigations are-beyond the means and powers of individual science workers or of- medical institutions, and need to be undertaken by an organized body with relays of workers and sufficient funds at its command to provide for the uninterrupted pursuit of the inquiries.Katz, of Hamburg, whom I have' previously quoted, re- mnarked: " It is to be deplored that Cohnheim's doctrine has so long found an extended acceptance, for the further deve- lopment of cancer research would have, through it, no value.A standstill would result from the fatalism which underlies this theory.The same may be said with regard to Ribbert's theory, which, though of far later date than Cohnheim's, is in pursuit and continuation of it."But a theory, if it has the evidence of truth, must be ninutely and impartially examined, even though it seems to 1ead to a conclusion which we might wish to esape.There is, however, no occasion for so pessimistic a view as that of Katz.The "tumour-germ" theory, at least does this: it convinces us of the local origin of cancer, and of the positive curability of it if removed quite early and com- plOtely.Of course, it does not guarantee one against the for- mation of another malignant new growth, any more than the uepair of a broken bone guarantees one against the occurrence of another fracture.It should also encourage the early and more frequent removal even of benign growths.Future researches may reveal a method whereby a special inhibitory influence may be brought to bear upon the cells of the "tumour matrix," on the lines tried by Foulerton; or a restraining, even a strangulating, effect upon the tumour cells by the tumour matrix may be produced, as suggested by Marshall.But in any case, we can reasonably hope and expect that the organized researches now commenced by the Colleges will in time yield much information as to how to pre- vent cancer by teaching us what are the real agencies which stimulate it into existence.In bringing these remarks to a conclusion I will borrow the description recently given by Mrs. Crawford of the mind of the late M. Thiers.and apply it to the theory founded by Durante and Cohnheim."It has search-light luminosity.Like radium, it keeps burning brightly, without consuming itself.";And, I would add, it will not only remain active and brilliant to the end, but it will, I believe, shed more and more light on the etiology of canoer with every fresh addi- tion made to the science of embryology and to our knowledge of tumours.