Abstract
LONDON Royal Society, May 3. W. D. WRIGHT: The measurement and analysis of colour adaptation phenomena. There is a main process of adaptation that operates through the regeneration of a photosensitive substance at a constant rate. The instantaneous response aroused by a stimulus is directly proportional to the magnitude of the latter, but owing to the process of adaptation, the response is rapidly reduced to an approximately constant level. This is the true interpretation of the constancy of the Fechner fraction, as opposed to the suggestion that the response is proportional to the logarithm of the stimulus. By locating the three hypothetical stimuli in the colour triangle corresponding to those sensations that can be modified in intensity, but not in colour, no matter what the colour of the adaptation may be, it has been possible to determine the fundamental response or excitation curves. R. J. LUDFORD: Factors influencing the growth of normal and malignant cells in fluid culture media. Significant differences have been found in the behaviour of different strains of tumours in mouse and rat serum. Some tumours have not been grown as sheets of malignant cells in either mouse or rat serum; other tumours have given good sheet growths in mouse serum but not in rat serum; while still others have grown in both sera. It is suggested that whether or not cells form sheets from explants in a fluid medium depends upon the adhesion of the cells to glass in that particular medium, rather than upon growth-promoting or growth-inhibiting properties of the medium. The presence of large numbers of active cells of the macrophage type interferes with sheet formation by malignant cells in fluid media. This is regarded as due partly to crowding out of the malignant cell on the surface of the cover glass, and partly to the phagocytic activities of the polybiasts. It may be the activity of cells of this type accumulated around a tumour graft in an ‘immune’ animal which prevents its growth.
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Societies and Academies. Nature 133, 734–736 (1934). https://doi.org/10.1038/133734a0
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DOI: https://doi.org/10.1038/133734a0