132 



quickly after fermentation ceases, partly because as a strict anaërobe 

 it cannot withstand traces of oxygen diffusing into the medium, 

 partly perhaps owing to the action of the organic acids formed in the 

 fermentation. 



This observation made Beijerinck reaUze that a cultivation of the 

 stomach sarcina in vitro would only succeed if the stomach contents in 

 which it was present were transferred immediately after their collecti- 

 on into a medium permitting optimal development. Neglect of this 

 point might well be responsible for the failure of earHer investigators 

 to cultivate the organism. 



It was only six years later that Beijerinck got the opportunity 

 to submit his hypothesis to an experimental test i). This test led to a 

 completely satisfactory result. The bottles of beer wort inoculated 

 with the fresh stomach contents of a patiënt entered quickly into a 

 strong fermentation, and the causative organism could be transferred 

 in exactly the same way as the soil organism. In other respects also 

 complete identity of the two organisms was established. 



The excellent monograph which Beijerinck's former collaborator 

 Smit in recent years has devoted to Sarcina ventriculi and some 

 related organisms, throws a clear light on the remarkable properties 

 of the representatives of this group2). Smit stresses that the wide 

 distribution of Sarcina ventriculi in nature seems quite opposed to the 

 extreme sensitivity of the organism when cultivated in pure culture. 

 A resolution of this paradox has not yet been ixached. Further work 

 on this subject seems most desirable, and may be of great importance 

 for our general insight into the conditions which determine the survi- 

 val of microbes in nature. 



Finally, it seems probable that the recent procedures for the pre- 

 paration and preservation of ensilage, based on the reputed absence of 

 microbial life under anaerobic conditions as soon as the acidity of the 

 medium corresponds to pH 4.0 or lower, may bef ore long lead also to 

 the realisation of the great practical significance of the fermentation 

 process discovered by Beijerinck 3). 



k. Investigations on acetic acid hacteria. 



The frequent occurrence of acetic acid bacteria in fermentation 

 industries leaves no doubt that already very early in his career Beije- 

 rinck became thoroughly familiar with various types of acetic acid 

 bacteria. Yet, it was not until 1898 that he decided to deal in a publi- 

 cation 4) with his experiences on this natural group of bacteria. The 

 reason for this decision was the circumstance that at the same time a 



ï) Proc. Kon. Akad. v. Wet. Amsterdam 13, 1237, 1911. 



2) Jan Smit, Die Garungssarcinen. Eine Monographie. Jena, 1930. 



3) Smit's experiments have shown definitely that development of Sarcina ventriculi 

 is possible in media having a pH only slightly above 1.1. 



t) Centralbl. f. Bakt. u. Parasitenk. II, 4, 209, 1898. 



