PREAMBLE 



This book has been conceived in consultation with the children of 

 the late Professor Kluyver. Colleagues, pupils, collaborators, and 

 other associates from well-nigh every period of his life have un- 

 stintingly responded to requests for contributions to the biographical 

 section. The result aims at bearing witness to a sense of solidarity and 

 reverence which is also manifested, as replica in effigy, by the bust 

 sculptured by Professor Wenckebach through the initiative of Kluy- 

 ver's pupils. This bust was installed in the new Laboratory of 

 Microbiology when the latter was being occupied; at that time, too, 

 the plaque of Beijerinck was moved thence from the now abandoned 

 old laboratory at the Nieuwelaan where the two scientists had con- 

 ducted their illustrious studies for so many decennia. 



A strong impetus to the publication of the 'Selected Papers' was 

 the desire to render comprehensible to future generations the influ- 

 ence that Kluyver's intellectual and human traits have exerted on 

 science and on his associates in the widest sense of the word. 



Referring to the Apology for more specific details, a brief account 

 of the composition of this book is here presented. 



Initially the possibility was considered of reprinting all of Kluyver's 

 publications. Closer scrutiny made it necessary to abandon such a 

 plan. In part this was motivated by the fact that many of the con- 

 cepts enunciated by Kluyver have long since been firmly incorporated 

 into microbiological science. Others, representing notable stages in 

 the development of this discipline at the time of their publication, 

 have lost some of their significance in the course of years on account of 

 later improvements in methodology and understanding. The scales 

 were turned by the decision to let Kluyver's work and personality 

 speak to as large an audience as possible; and this inevitably implied 

 a selection. 



Had this been confined to a choice from among the strictly original 

 scientific papers, the resulting collection would have given too one- 

 sided a picture of Kluyver's range of activities. Consequently a num- 



