Cell Proliferation under Continuous Irradiation

This is the authors' abstract. We don't add key points for this paper.

I have no need to say how great an honor it is to be invited to give the 3rd Failla Memorial Lecture. I shall always be grateful for the privilege of having known Dr. Failla, and for having learned something of his wisdom and his humanity. He was, to my mind, one of the first in recent times to revive the old tradition of true natural philosophy, to ignore the academic boundaries between the various scientific disciplines, and to recognize that an initial training in the physical sciences could itself be a passport into biological work. An interest in radiation was Dr. Failla's reason for coming into biology, and since then radiation has been the vehicle by which many have moved out from-dare I say it-the comfort of the physical sciences into the much more complex but fundamental study of living things. I do not know whether Dr. Failla ever called himself a radiobiologist, but if he did I am certain that he would not have wanted to define radiobiology. He, better than most, recognized that radiobiology is a subject with a double role in which the emphasis is continually changing. On the one hand, there is the study of the biological effects of radiation for practical ends. On the other, there is the use of radiation as a tool in the study of biological mechanisms. These two aspects of radiobiology are, of course, closely interwoven, but it is in its second role that the impact of radiation in scientific work and thought must be increasingly felt. It is not necessary here for me to enlarge on the applications and achievements of radiation as a tool in cellular and subcellular studies, and so today I shall be discussing some of its applications at higher levels of biological organization, where there has been less work done, but where the opportunities are certainly as great. The subject I shall take is the part that continuous irradiation can play in the study of the mechanisms of control of cell populations.