The paper is an extended summary of a study which is still in progress and which will be published in full elsewhere. A very brief resumé was given at the International Symposium on the Response of the Nervous System to Ionizing Radiation Chicago, September 1960. This communication only deals with the developed pathologic process; no reference is made to the attempts to trace pathogenesis or the extensive histological and histochemical studies involved in the later part of the work. Research was carried out at Brookhaven National Laboratory under the auspices of the U.S. Atomic Energy Commission.
The central nervous system was long considered to possess a very high degree of resistance to radiation—and statements to this effect occasionally still appear. It is manifest that there must be some qualification by reference to the part of the system exposed, the conditions and dosimetry of irradiation, and in experimental work the