. Biophysical research methods. Biophysics -- Research. \F. 300 400 700 800 500 600 < WAVELENGTH, m/i Fig. 3. A number of action spectra (^). The ordinates are I/I'o corrected to unity at the point of maximum action. (A) Hemolysis of erythrocytes. (B) Killing of a bacillus, E. coli. (C) killing of a yeast, Saccharomyces cerevisiae. (D) Erythema of human skin. (E) Vesiculation of a protozoan, Paramecium multi- nucronucleata. (F) Vision of an insect, Drosophila. (G) Tropic bending of the oat coleoptile. (H) Photosynthesis of the wheat plant. (/) Scotopic vision (rods) of the human eye. (/) Ph
. Biophysical research methods. Biophysics -- Research. \F. 300 400 700 800 500 600 < WAVELENGTH, m/i Fig. 3. A number of action spectra (^). The ordinates are I/I'o corrected to unity at the point of maximum action. (A) Hemolysis of erythrocytes. (B) Killing of a bacillus, E. coli. (C) killing of a yeast, Saccharomyces cerevisiae. (D) Erythema of human skin. (E) Vesiculation of a protozoan, Paramecium multi- nucronucleata. (F) Vision of an insect, Drosophila. (G) Tropic bending of the oat coleoptile. (H) Photosynthesis of the wheat plant. (/) Scotopic vision (rods) of the human eye. (/) Photopic vision. (K) Photosynthesis by purple sulfur bacteria, Spirillum ruhrum. The curve reaches a maximum about 900 m/n. The original references are cited in Blum {2). Accuracy of some of these action spectra may be questioned; but wavelength limits are probably nearly cor- rect, and this alone serves to illustrate spectral range of such effects. subject of action spectra, the systems studied and the problems of measurement are so diverse that very few general rules can be laid down. The purpose for which the action spectrum is obtained may dictate the mode of expression. For example, in illuminating engi- neering, and in many other problems involving human vision, one is concerned with the amount of incident energy required to stimulate the visual response (Fig. 4), and this is usually measured in ergs or some other energy unit. On the other hand, if one wishes to deter- mine the nature of the light absorber, , the photosensitive retinal pigment in this case, a mode of expression is desirable that permits one to deal in terms of the number of quanta absorbed. To estimate the absorption, indirect measurements are often required, sometimes. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Uber, Fred Murra
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