eet | ae | TTT Ty j |. i Los ry ey pf ea — aessusceserssess ti silisds SOO; "Gee oe #00 tet eseveas 400 a . See, . 200 ober 3 we -— * a 600 rT IMPULSE LETHALITY &Dy om HB 1600 4 ™ t+ tt 6 810 [5 20 30 40 a tuted Et 69 Gi00 TIME FROM BEGINNING OF EXPOSURE I [O20 soo4co GOO (DAYS) Figure V. A plot of the impulse lethality funetion versus time from the beginning of exposure in duratton-of-ltfe experiments. The data are for LAF1 male (solid line) and female (broken line) mtce exposed to cobalt-60 gamma radiation. Data from Sacher and Grahn [Sh]. However, the formulation of this theory is not sufficiently developed and may be regarded as a first attempt towards a more comprehensive treatment. 119. In another paper Sacher, Grahn, Fry et al. [S5] examined the Late ef- fects of gamma-radiation in respect to two major categories of effects: the incidence of tumours of the reticular tissue and the life-shortening induced by all causes other than the reticular tumours. The data were obtained from male and female mice of four different genotypes exposed in duration-of-life experiments (6, gamma rays, 0.3 to 56 R/day). In agreement with that ob- served on the LAF1 mouse [S4] the data showed that the log mean after-survival plotted as a function of the daily dose followed a very nearly straight line. 120. The Gompertz transforms of these data (see Figure VI) for all causes of death were slightly convex upward and formed a fan of lines of increasing slope with increasing dose-rate with small differences between genotypes. When the