SIR HENRY DALE, chairman of the Medical Research Council's Committee on the medical and biological applications of nuclear physics, has commented (Lancet, 399, March 16, 1946) on the letters written to the Lancet by Dr. Wiesner and Mr. Kenneth Walker on the biological dangers of atomic fission (see Nature, Feb. 23, p. 222). The issues raised by these letters are, Sir Henry Dale agrees, undoubtedly important ; “but,” he continues, ”having knowledge of what has been done to deal with them, I can say with assurance that all the dangers mentioned in the two letters have received full consideration by those in charge of the Canadian and British Atomic Energy Projects, in connexion with which an elaborate health organisation has been built up”. The possibility of genetic effects is being kept in mind and “authoritative opinion is being kept in touch with the nature of the risks to which workers concerned with an atomic energy installation might be exposed, and will require to be satisfied that these are reduced to a level which is not significant....”New information hitherto covered by security restrictions will be released as soon as possible. “A study of the extensive existing literature on this subject,” concludes Sir Henry, ” would make possible a more correct assessment of the dangers involved than that which the letters of Dr. Wiesner and Mr. Walker might be taken to suggest.” Meanwhile some work on the toxicity of uranium is the subject of an annotation in the British Medical Journal (397, March 16,. 1946). Fair-hall (Physiol. Rev., 25, 182; 1945) has reviewed the inorganic industrial risks and says that uranium salts are very toxic and may cause chronic nephritis and degeneration of the liver. Gustafson, Koletsky and Free (Arch. Intern. Med., 74, 416 ; 1944) reported severe tubular necrosis of the kidneys in dogs to which uranyl nitrate had been given intravenously, but sodium citrate, given either by the mouth or intravenously, protected the kidney against uranium poisoning. This was confirmed by other American workers. The reason why sodium citrate should protect the kidney in this way is apparently not known.