vi Preface 



To some readers this book may form an introduction to the 

 work of the Ciba Foundation, and it may be helpful to add a 

 few words about its interests. 



Under its eminent Trustees, the Foundation is engaged in a 

 number of activities with the purpose of improving co- 

 operation in medical and chemical research between workers 

 in different countries and different disciplines. At its house in 

 London the Foundation provides accommodation for scientists, 

 organizes conferences, conducts a medical post-graduate ex- 

 change scheme between Great Britain and France, arranges 

 a variety of informal discussions, awards two annual lecture- 

 ships, and is building up a library service in special fields. 

 The Foundation assists international congresses and scientific 

 institutions, and it is hoped that in its hospitality, its meetings, 

 and in such a volume as this, it is also usefully helping the 

 individual scientist. 



