140 



"Unter "Oligonitrophilen" verstehe ich diej enigen Mikroben, welche 

 bei freier Konkurrenz mit der übrigen Mikrobenwelt sich in Nahr- 

 medien entwickeln, ohne absichtlich zugefügte Stickstoffverbindun- 

 gen, aber auch ohne dass Fürsorge getroffen wird, urn die letzten Spu- 

 ren dieser Verbindungen zu entfernen. Sie haben das Vermogen, den 

 freien atmospharischen Stickstoff binden und zu ihrer Ernahrung 

 verwenden zu können." 



Herewith, apparently, Beijerinck wished to state at once his 

 conviction that nitrogen fixing power is not at all restricted to one or a 

 few specific organisms, but is typical for large groups of microbes. 



Characteristic of Beijerinck's broad views on the problem is that 

 he also included the photosynthetic organisms in his experiments. In 

 doing so he came to the conclusion, already mentioned in the chapter 

 on the pure culture of the green and the blue-green algae, that the 

 latter group contains several nitrogen fixing species. 



The second part of the paper, which deals with the heterotrophic 

 oligonitrophilous organisms, opens with a discussion of Winograd- 

 sky's experiments. Beijerinck remarks that his own experience led 

 him to the conviction that the development of Clostridium Pastoria- 

 num is only possible in media which contain small quantities of 

 nitrogen compounds, but this statement does not imply doubt 

 regarding the nitrogen fixing power of the organism, since Beije- 

 rinck adds that the same holds for the nitrogen fixing organisms 

 discovered by himself . 



Then follows a passage which seems sufficiently interesting to be 

 cited again in f uil : 



"Meine Versuche sind von denj enigen von Winogradsky inso- 

 weit verschieden, dass ich ent weder nur Aërobiose ermöglicht, oder 

 den Sauerstoffzutritt doch in der Weise gefördert habe, dass die 

 Buttersauregarung unterdrückt, oder sehr geschwacht war. Auch ver- 

 wendete ich andere Kohlenstoffquellen wie er. Demzufolge kam ich 

 zur Entdeckung einer noch nicht beschriebenen oligonitrophilen 

 Bakteriengattung, welche zu den Aërobien gehort. Ich werde diese 

 durch die Grosse der Individuen leicht kenntliche GdXiVing Azotohacter 

 nennen. Bisher erkannte ich davon 2 sehr verschiedene Arten. Die 

 eine, A. chroococcum, ist sehr allgemein in Gartenerde, sowie in allen 

 andern fruchtbaren Bodenarten, die andere ebenso verbreitet im 

 Kanalwasser zu Delft." 



It has been deemed interesting to reproduce here in Plate XIII the 

 page of Beijerinck's laboratory note-book on which thensuneAzoto- 

 hacter chroococcum is used for the first time. 



By the way it may be remarked that this page gives proof that 

 Beijerinck was also in full action on old year's day. 



After reading this startling announcement of what since has been 

 proved to be a truly great discovery, one will be eager to learn more 

 details regarding the dif f erences in procedure which decided that 



