CHAPTER XVIII 



BACTERIAL ROOT NODULES 



Although Beijerinck's microbiological work is amply discussed in 

 Part III of this biography, we should like to give here a brief discus- 

 sion of his fundamental work on bacterial root-nodules. It was through 

 this research that Beijerinck's fame as a bacteriologist was estabUs- 

 hed. Still the work has a definitely botanical side too. 



One finds the bacterial root-nodules mentioned already in Beije- 

 rinck's doctorate thesis i) with these words: "Only in a few cases 

 are the galls better known than their causal parasites. This is the 

 case with the root nodules of the Papüionaceae" . Herewith the cause 

 of Beijerinck's later interest in these formations becomes clear, and 

 it also explains his statement: "Die Papilionaceenknöllchen sind 

 Bacteriencecidien" . 



We recall that by 1888, when Beijerinck's classical investigation 

 "Die Bacteriën der Papilionaceen-Knöllchen" 2), appeared, views on 

 the nature of leguminous root nodules had already been promulgated 

 by older investigators. Beijerinck mentions a few of these views in 

 a footnote at the beginning of his paper, viz., the observations of 

 Woronin in 1866 on the presence of living bacteria in root nodules, 

 those of Frank on the non-occurrence of nodules during the devel- 

 opment of Leguminosae in sterile soil, those of Marshall Ward, on 

 the occurrence of nodules when crushed nodules were added to nodule- 

 free plants grown in sterile soil. But L. Hiltner in his excellent sur- 

 vey in Lafar's Handbuch der Technischen Mykologie 3) very pro- 

 perly emphasizes that in 1 887 there was still doubt as to the nature 

 of the nodules and that the doubt was strengthened since J. Brunc- 

 HORST had put forward the view that the little bodies in the nodules 

 were protein particles which resembled bacteria, but which should 

 properly be designated as "Bakteroiden". Rightly, Hiltner adds: 

 "Der Umschwung vollzog sich ein Jahr spater, also im Jahre 1888, 

 als Beijerinck die Pilznatur dieser angeblichen Scheinbakterien da- 

 durch ausser Zweifel st elite, dass er diese aus den Knöllchen abschied 

 und ausserhalb derselben auf künstlichen Nahrböden weiter züchte- 

 te". 



1) Academisch Proefschrift, Utrecht 1877 {Verzamelde Geschriften 1, 8-80). 



2) Die Bacteriën der PapiUonaceen-Knöllchen, Botanische Zeitung 46, 725-735, 

 741-750, 757-771, 781-790, 797-804, 1888 (Verzamelde Geschriften 2, 155-188). 



3) Drifter Band, Jena 1904-1906, p. 32-34. 



