26 



various Volvacaceae, deserve a special mention. In addition Jacobsen 

 most unselfishly did an enormous amount of work to support Beije- 

 rinck's researches during the second half of his academie career. 

 Moreover, he considerably lightened Beijerinck's task by taking over 

 a part of the instruction of the less advanced students. The favourable 

 influence Jacobsen had on the course of affairs at the laboratory in 

 the Nieuwe Laan cannot easily be overrated. 



Also N. L. SöHNGEN largely contributed to the scientific standing 

 of the institute, as appears from the numerous articles published by 

 him during his stay at the Delft Laboratory (Cf. Appendix C). Söhn- 

 GEN was the first to take a Doctor's degree at Delft, after the new 

 Higher Education Act made that possible by bringing about the 

 conversion of the Polytechnical School into a "Technische Hooge- 

 school". Söhngen's thesis dealing with the production and consump- 

 tion of methane and hydrogen in nature has now generally been re- 

 cognized as a classic. Yet it seems that at first Beijerinck did not 

 f eel much inclined to accept this thesis as such ; apparently he shrank 

 from the troubles involved. 



Soon after he had obtained his doctorate, Söhngen left Delft and 

 acted as bacteriologist to some margarine factories in Rotterdam and 

 in Middelburg. In this period he published several papers, some on the 

 bacterial decomposition of fats, and others on urea fermentation. On 

 December Ist, 1911, however, he accepted the post of assistant at 

 Delft and held that post until September 1915. In this second Delft 

 period he studied amongst other subjects the mineralization of hy- 

 drocarbons like benzene, kerosene, etc. He also published an extensive 

 study dealing with the factors causing offensive odours in the canals at 

 The Hague. 



Söhngen's independent character prevented him from cooperating 

 closely with Beijerinck. In 1915 Söhngen became Director of the 

 Microbiological Division of the Government Agricultural Experiment 

 Station at Groningen. In 1917 he was appointed professor of micro- 

 biology at the Agricultural College at Wageningen, where he remained 

 until his death in 1934. Over this period he did a great deal to propag- 

 ate the application of Beijerinck's science to agricultural problems. 



We have no space to mention the work of the other assistants who 

 were for the most part temporary. 



The frequently impossible demands Beijerinck made on his 

 assistants often caused somewhat strained relations between them 

 and him. It was no light task to be his demonstrator. The junior 

 might do his best, but was often grumbled at by the professor just 

 before the lecture. At such moments Beijerinck was always more 

 or less nervous, and often managed to set his demonstrator on edge 

 as well. Sometimes the poor fellow was the target for a sneer during 

 the lecture for some "carelessness" or other, and after the lecture, 

 when the experiments for next time were discussed, his sins were some- 



