PREFACE 



The Ciba Foundation, London, is an educational and 

 scientific charity founded by a Trust Deed made in 1947. 

 Its distinguished Trustees, who are wholly responsible for its 

 administration, are The Rt. Hon. Lord Adrian, O.M., F.R.S.; 

 The Rt. Hon. Lord Beveridge, K.C.B., F.B.A.; Sir Russell 

 Brain, Bt. ; The Hon. Sir George Lloyd-Jacob, and Mr. 

 Raymond Needham, Q.C. The financial support is provided by 

 the world-wide chemical and pharmaceutical firm which has 

 its headquarters in Basle, Switzerland. 



The Ciba Foundation forms an international centre where 

 workers active in medical and chemical research are encour- 

 aged to meet informally to exchange ideas and information. 

 It was opened by Sir Henry Dale, O.M., F.R.S., in June 1949. 



In the first seven years, in addition to many part-day dis- 

 cussions, there have been 40 small international symposia, 

 each lasting two to four days and attended by from twenty- 

 five to thirty outstanding workers from many countries. Other 

 symposia are planned at the rate of five or six a year. 



The informality and intimacy of these meetings have per- 

 mitted discussion of current and incomplete research and 

 stimulated lively speculation and argument. They have also 

 been the occasion for reference to much published and un- 

 published work throughout the world. 



The reader will probably be well aware that there have been 

 many conferences, national, international and inter-disciplin- 

 ary, in recent years on the effects and hazards of radiation. 

 This is partly due to rapid progress and expansion in this field 

 of research, and partly to a quickening interest in the signifi- 

 cance of the work shown by other scientists and by laymen. 

 Most of these conferences have been on a fairly large scale, 

 valuable for exchanges of information but usually affording 

 little opportunity, except privately, for thorough discussion. 



