127 



RINCK'S butyl ferment is not identical with Clostndium acetobutylicum, 

 the organism nowadays generally used in the technical production of 

 butyl alcohol. In the fermentation caused by the latter species, not 

 isopropyl alcohol, but the closely related acetone, occurs. 



Apart from a short notice on an enrichment procedure for his 

 butyric acid bacterium, Granulobacter saccharobutyricum l ) , BEIJE- 

 RINCK devoted only one more publication to the representatives of 

 the genus in question. This study, made jointly with his assistant A. 

 H. VAN DELDEN, dealt more especially with the bacteria active in the 

 retting of flax 2 ). 



In May 1903 a committee had been appointed, charged with the 

 task of investigating the possibility of promoting the home working 

 up of flax grown in the Netherlands. Until that time, by far the greater 

 part of the flax harvested in the northern provinces of the Netherlands 

 (Friesland and Groningen) was sent to Belgium and submitted to a 

 retting process in the river Lys near Courtrai. BEIJERINCK accepted 

 the task of studying the applicability of the warm water retting pro- 

 cess, introduced into Belgium some years before. 



In BEIJERINCK and VAN DELDEN'S study the fundamentals of the 

 retting process are clearly exposed. From an anatomical study of the 

 flax plant, convincing evidence was derived that retting is essentially 

 a process of pectin fermentation which liberates the fibres from the 

 surrounding parenchyma and the central woody stem. It is pointed 

 out that a satisfactory retting procedure depends on a successful 

 enrichment culture of pectin-fermenting bacteria. It is then shown that 

 at least under the chosen conditions of warm water retting, pectin 

 fermentation is due to the action of a plectridium-forming Granulo- 

 bacter species, to w r hich the name of Gr. pectinovorum is given 3 ). This 

 bacterium which, in contrast to the other species of the genus, also 

 readily ferments pectin in synthetic media, is apparently identical 

 with the Plectridium pectinovorum described a year before by STOR- 

 MER 4 ). Yet, BEIJERINCK'S careful observations added a good deal to 

 our knowledge of the organism. Besides this principal agent of the 

 retting process another new species, viz., Granulobacter urocephalum 

 was encountered, and a description of this species was given, though it 

 is apparently only of secondary importance in the retting process. 



Finally mention should here be made of a study published by 

 BEIJERINCK, jointly with his collaborator DEN DOOREN DE JONG, at 

 the end of his scientific career, i.e., shortly after his retirement from 

 the chair at Delft 5 ). The paper bears the short title "On Bacillus 

 polymyxa" and deals with the remarkable bacterium already described 



1) Centralbl. f. Bakt. u. Parasitenk. II, 2, 699, 1896. 



2 ) Arch, neerl. d. sciences exa.ctes et naturelles Ser. II, 9, 418, 1904. 



3 ) Cf., however, A. D. ORLA-JENSEN und A. J. KLUYVER, Zentralbl. f. Bakt. II, 101, 

 1939. 



*) K. STORMER, Mitt. d. deutschen landwirtsch. Gesellschaft p. 193, 1903. Cf. 

 abstract in Centralbl. f. Bakt. u. Parasitenk. II, 11, 66, 1904. 

 5) Proc. Kon. Akad. v." Wet. Amsterdam 25, 279, 1922. 



