126 



Although this statement is perhaps not fully justified as regards 

 Grimbert's results i), it cannot be denied that Beijerinck's paper 

 meant considerable progress ; it may even be regarded as the founda- 

 tion stone of our knowledge of a fermentation process which in recent 

 years has obtained such a considerable economie importance 2). Beij- 

 erinck's contribution is chiefly of importance, because it supplies 

 detailed prescriptions for isolation of the causative organism with the 

 aid of well-devised enrichment experiments. Another valuable point 

 is the recognition of the close relationship between the "butyl ferm- 

 ent" and the other spore-forming sugar-fermenting bacteria of which 

 two anaerobic, butyric acid f orming, types are described together with 

 Prazmowski's facultatively anaerobic species, Bacillus polymyxa. All 

 these species were united by Beijerinck into one genus for w^iich the 

 name Granulobacter was proposed on the ground of the common 

 property that under certain conditions the cells take the form of 

 clostridia staining blue on addition of iodine, due to the presence of a 

 reserve carbohydrate, to which the name granulose was given. 

 Besides the diagnosis of the genus, Beijerinck gave a full description 

 of the four Granulobacter species with which he had become intimately 

 acquainted. 



Special attention may be called to Beijerinck's intuition which 

 made him at once discriminate between the sugar- and the lactate- 

 fermenting butyric acid bacteria. The recent work of van Beynum 

 and Pette 3) has thrown full light on the great practical importance of 

 this differentiation. 



The greater part of Beijerinck's paper supplies an exemplary 

 description of his butyl ferment, Granulobacter butylicum. Both its 

 morphological and its physiological characteristics are dealt with in 

 great detail. Whilst Beijerinck thought that besides the butyl alco- 

 hol, normal propyl alcohol was produced 4), it has since been establish- 

 ed with certainty that the organism in question produces isopropyl 

 alcohol. In 1929 van è>er Lek 5) revived Beijerinck's organism 

 from an old dried spore culture labelled by Beijerinck in 1893, the 

 bacterium having remained viable in its resting stage for at least 36 

 years ! van der Lek then made accurate determinations of all ferm- 

 entation products and found that isopropyl, and not normal propyl, 

 alcohol was always present in considerable amounts in the neutral 

 volatile fraction. He thereby offered definite evidence that Beije- 



1) L. Grimeert, Ann. de l'lnst. Pasteur 7, 353, 1893. 



2) Significant in this respect is Beijerinck's remark that, if butyl alcohol were a 

 product of technical importance, it could easily and cheaply be prepared by the fer- 

 mentation method. 



3) J. VAN Beynum und J. W. Pette, Zentralbl. f. Bakt. II, 93, 198, 1935; Ibid. 94, 

 413. 1936. 



") In a later paper (cf. Proc. Kon. Akad. v. Wet. Amsterdam 1, 14, 1898) Beije- 

 rinck even goes as far as to say that his organism produces much more propyl alcohol 

 than butyl alcohol and suggests that, therefore, the name Granulobacter propylicum 

 would be more appropriate. This, evidently, is a lapsus. 



5) J.B. van der Lek, Onderzoekingen over de butylalkoholgisting. Delft, 1930. 



