PI. III 



-v 



Henriëtte Wilhelmina 



Beijerinck (1847-1937); 



elder sister of the scientist. 



Frederik Leonard Beijerinck 



(1844-1883); brother of the 



scientist. 



Johanna Hermana Alida 



Beijerinck ( 1 849- 1 923) ; 



younger sister of the 



scientist. 



M. W. Beijerinck as a student, at the 

 asre of 20. 



