24 



dience was so greatly taken aback that Professor HOOGEWERFF felt 

 called upon to make amends by a more cordial speech. Then BEIJE- 

 RINCK and his guests had supper, which ended in great exasperation to 

 the host. 



This is not the place to deal with the scientific activity displayed by 

 BEIJERINCK and his collaborators during the twenty-four years he 

 was in charge of the laboratory at the Nieuwe Laan. For a sketch of 

 BEIJERINCK'S scientific method the reader is referred to Chapter VII, 

 whilst a detailed account of the more important investigations carried 

 out during this period may be found in Part II and III of this bio- 

 graphy. 



It seems desirable, nevertheless, to say here something about BEIJ- 

 ERINCK'S relations with his assistants and students. 



BEIJERINCK was exceptionally lucky in the selection of his as- 

 sistants, and this circumstance materially contributed to the success 

 of his scientific work. Though it is impossible to mention all his as- 

 sistants here - - a complete list is given in Appendix B - a few words 

 may be devoted to some of the more prominent amongst them. Plate 

 VI presents their contemporary portraits. 



BEIJERINCK seems never to have lacked an appreciation of the 

 importance of salaries, and he succeeded in obtaining for his assistants 

 a remuneration considerably higher than the normal. Thus, his as- 

 sistants had no immediate reason to be on the look-out for better- 

 paid jobs, and several of them remained in office for relatively long 

 periods. 



BEIJERINCK started his work in 1895 with only one assistant, A. H. 

 VAN DELDEN, a young technologist who had taken his degree only 

 shortly before. Although VAN DELDEN entirely lacked experience in 

 microbiology, he soon developed into a very able bacteriologist. VAN 

 DELDEN stayed with BEIJERINCK until 1904, when he accepted the 

 post of bacteriologist of the Rotterdam Water Works, of which he 

 later became an assistant director i). It is certain that the period of 

 VAN DELDEN'S assistantship covers that of BEIJERINCK'S greatest 

 achievements in the microbiological field. It is difficult to estimate 

 correctly the part which VAN DELDEN had in many of BEIJERINCK'S 

 investigations, but there is good reason to suppose that VAN DEL- 

 DEN'S share was far from negligible. BEIJERINCK did not always stop 

 to consider the justice of giving credit where credit was due in the 

 publication of results of joint work. The fact that BEIJERINCK'S 

 strongly-marked individuality ceded to VAN DELDEN the right to join 

 his name to BEIJERINCK'S in papers on nitrogen fixation, on Bacillus 

 oligocarbophilus, and on the retting of flax, leaves no doubt that VAN 

 DELDEN'S contributions to these studies must have been substantial. 

 VAN DELDEN published separately an important paper on sulphate 



>) VAN DELDEN died in 1926, at the comparatively early age of 52. 



