. Biophysical research methods. Biophysics -- Research. XIV. X RAYS AND X IRRADIATION 471 conditions. These observations have been made on such biologically different materials as plant and animal viruses, bacteria, Dros^ophila sperm, sunflower and mustard seed, mold spores, yeasts, and pnj- tozoa. The graph presented in Figure 7 shows some of these data, together with literature r(>ferences. The logarithm of the per cent survivors is sho\\Ti as the ordinate of the graph. The abscissas repre- sent the X-ray doses in roentgens. It will be noted that the survival curves for each species are q
. Biophysical research methods. Biophysics -- Research. XIV. X RAYS AND X IRRADIATION 471 conditions. These observations have been made on such biologically different materials as plant and animal viruses, bacteria, Dros^ophila sperm, sunflower and mustard seed, mold spores, yeasts, and pnj- tozoa. The graph presented in Figure 7 shows some of these data, together with literature r(>ferences. The logarithm of the per cent survivors is sho\\Ti as the ordinate of the graph. The abscissas repre- sent the X-ray doses in roentgens. It will be noted that the survival curves for each species are quite different, both in their form and in 100 80 40 O tr 20 Id a. 10 ^ ^== (6) ~(?r V â ^:^ ^^ ^^ vd 44) \ > \ V â (2^. 40000 DOSE, 80000 Fig rays. 2000 0 DOSE. r. 7. Survival curves for several species irradiated with known doses of X Forms taken by survival curves illustrate various complexities in X-ray effects requiring Poisson equations of more and more terms to explain them. (1) Drosophila eggs (43); (2) yeast cells (53); (S) Drosophila sperm (26); (4) colon bacillus (53); (5) Drosophila sex-linked lethals (26); (6) ordinary tobacco mosaic virus (23); (7) and (8) Sarrhnromyces ellipsnileus ( and A.) (21); (9) Colpidium colpoda (10). the amount of radiation necessary to produce a given lowering of the survival curve. As will be seen later, both these factors are important in the interpretation of the radiation effects and the biological changes they make. Another type of observation is that of the rate of mutation in the individual genes of an organism when exposed to radiation. Similar data may also be gained for the breakage of chromosomes by X rays, resulting in the formation of inversion, translocation, and deletion in the chromatin structure. Data on lethal mutations in the sex chromosome of Drosophila representing gene mutations and chromo- some deficiencies follow the simplest type of equation. Where. Please note that these images are extracte
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