17 



the Amsterdam Academy in 1883 by Professors de Vries and Rau- 

 WENHOFF. As demonstration material Beijerinck added to the 

 manuscript a branch showing gum formation as the result of one of 

 his infection experiments. 



In May 1884 Beijerinck was elected a member of the "Koninklijke 

 Akademie van Wetenschappen" at Amsterdam (Royal Academy of 

 Sciences) ; soon afterwards he was installed. Once in the Academy he 

 came into regular contact with prominent scholars of that time, such 

 as HuGO DE Vries, C. A. J. A. Oudemans, F. C. Donders and Th. W. 

 Engelmann. In later years he came into close touch with the phy- 

 siologist C. A. Pekelharing. At Wageningen, together with Adolf 

 Mayer, he founded the "Natuurwetenschappelijk Gezelschap", a 

 societ}^ for the encouragement of the natural sciences. 



On January 22nd, 1 879 his father died, and he then went to live with 

 his sisters Henriëtte and Johanna in the Dijkstraat at Wageningen. 

 This should have made his hitherto solitary life more agreeable. Yet 

 Beijerinck remained more or less gloomy, as appears from the fol- 

 lowing complaint found in the diary of his sister Henriëtte: "On our 

 walks he of ten remains silent for hours, which always makes me slight- 

 ly annoyed with him". Henriëtte, then holder of the teaching-certifi- 

 cate for drawing in elementary schools, helped her brother a great 

 deal in drawing beautiful botanical pictures for teaching purposes. 

 Sister Johanna, a school-teacher, assisted him to translate his articles, 

 particularly into English. The trio led a rather lonely life, and mixed 

 with very few people in Wageningen. However, Beijerinck came on 

 friendly terms with his colleague Otto Pitsch and with Dr. M. Kreu- 

 nen, a teacher of the classical languages at the Gymnasium. On 

 Sundaj/s they of ten made long walks together i). 



Professor Moll from Groningen and particularly van 't Hoff — 

 not yet 30 years old and already a professor in the University of 

 Amsterdam — sometimes came to see Beijerinck and his sisters. 



In later years also the family received much friendship from van 

 't Hoff and his wife, Mrs. J. van 't Hoff-Mees. It was owing to 

 them that Henriëtte was enabled to continue her studies at Amster- 

 dam in order to work for the teaching-certificate for drawing in 

 secondary schools. With Henriëtte away during the latter years of his 

 residence at Wageningen, Beijerinck was left with only his sister 

 Johanna. A deep sorrow was caused by the tragic death of their bro- 

 ther Frederik on December 29th, 1883. Beijerinck was greatly di- 

 stressed by this bereavement. 



In other repects also his life at Wageningen was getting less 

 pleasant. His standing with the direct or of the Agricultural School 



1) The friendship with Dr. Kreunen lasted till the latter's death. There is no 

 doubt that Dr. Kreunen rendered Beijerinck numerous valuable services. When 

 new microbe species had to be named Beijerinck sent a brief description of the 

 more typical properties of the organism to Kreunen who then proposed an appropria- 

 te Latin name. 



M. W. Beijerinck, His life and his work. 2 



