The bearing of comparative and experimental investigation on the association of some forms of cancer with chronic irritation / by E.F. Bashford.

  • Bashford, Ernest Francis, 1873-
Date:
1914
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Licence: In copyright

Credit: The bearing of comparative and experimental investigation on the association of some forms of cancer with chronic irritation / by E.F. Bashford. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Dr. Murray’s experiments demonstrated that by in-breeding cancerous stock it has been possible almost to double the frequency of cancer in the case of mice whose mothers and grandmothers have suffered from cancer of the breast. Other experimental methods have shown that this increase is not due to a constitutional modification suitable for cancerous growth throughout the body as a whole, because mice with the hereditary taint do not offer a more suitable soil for the growth of tumours than the animals not so tainted. These experiments point to a localised tissue susceptability rather than to a constitutional liability to the disease. When chronic irritation has preceded the development of cancer the hereditary factor may predispose the tissue to cancerous change during the prolonged proliferation produced by the chronic irritation. One of the most striking facts is that the disease does not develop in all persons exposed to the same conditions. Therefore, for this and other reasons, the relation between chronic irritation and cancer is spoken of as “ mediate.” I now pass to a different kind of experiment designed to throw indirect light upon the mediate relation between chronic irritation and cancer, by ascertaining whether the characters of a cancer remain constant or vary. This investigation has only been made possible by studying many different kinds of tumour during prolonged propagation by transplanting from one mouse to another over and over again. At each transplantation the tumour suffers a trauma and its structure is completely disintegrated. The ready-made tumour cells are maintained in a state similar to that obtaining under chronic irritation. These observations fall into two main groups, as regards structure, and as regards powers of growth, and other more subtle properties. Briefly, the diapositives demonstrate that the characteristics originally shown by a tumour are retained with great constancy; but, exceptionally, marked variations may occur, both in structure and in powers of growth. Characteristic structure may be entirely lost, and a wholly undifferentiated cell mass may result, and remain during many years of cultivation. Other powers, such as that which leads to the production of sarcoma, may he lost. Before passing to the consideration of alterations in the powers of growth, it is necessary to explain the methods devised to study them by referring to what are known as the immunity reactions, but more correctly as the resistance which can be induced against the growth of the cancer cell. This resistance can only be induced by the tumours or tissues of the same species as that to which the cancer belongs. Normal tissues produce a higher degree of resistance and one which lasts longer than docs tumour
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