Abstract
[longdash]The problem of tolerance dose and X-ray protection has been reviewed. It has been recognized that various effects such as skin ulceration, sterility, anemia and even death may result from exposure to ionizing radiation in amts. not greatly exceeding those which accumulate in comparatively short periods of time in various laboratories, shops and clinics; that for such effects there are threshold levels of exposure ; that other changes, such as premature aging and neo-plasia may appear long after exposure; that for still other effects, irradiation induced mutations, there appears to be no threshold level of exposure; and that there is roughly a factor of 100 difference between the accepted permissible dose of O.lr/day and cosmic and earth radiation to which everyone is continuously exposed.