Pflanzenkrankheiten. — Bacteriologie. 201 



caused by fun<j:i. Ot" these Cladosporiinn herbanan, producing black 

 Spots is the only fungus that has become speciall}'^ adapted for 

 flourishing on bccf. It is not pathogenic and the only bad cffect 

 caused b}- its presence is the unsightl}'' appearance of the meat. 

 and consequent deterioration in value. 



A list of other fungi found on chilled beef is included. 



A. D. Cotton. 



Moekeridge, F. A., Some conditions influencing the 

 tixation of nitrogen bv Azotohacter and the growth of 

 the organism. (Ann. Bot. XXVI. p. 870—888. July 1912.) 



The principal conclusions arrived at are as follows. Calcium 

 and magnesium carbonate or basic slag used as neutralising agents 

 are more advantageous than sodium hydrate; the last mentioned 

 substance acts in fact as a depressant. 



Basic slag is an excellent Substitute for calcium carbonate for 

 neutralising the culture medium and acts as a tonic for nitrogen 

 fixation , increasing it by 23% • O'^^o of basic slag gives the maxi- 

 mum fixation of nitrogen. 



Good aeration of the cultures by means of sand slopes or shal- 

 low cultures is strongl}^ recommended, it ensures a more rapid, 

 rigorous and health}^ growth. 



Once a good growth is obtained the yield of fixed nitrogen 

 appears to be practicall}'' proportional to the amount of food sup- 

 plied. T. Goodey (Rothamsted). 



Przibram, K., Ueber die Brown'sche Bewegung nicht 

 kugelförmiger Teilchen. Mitt. Inst. Radiumforschung. 

 XXV. (Anzeiger ksl. Akad. Ak. Wiss. Wien. XXV. p. 458. 1912.) 



Die Beziehungen zwischen der mittleren Brown 'sehen Ver- 

 schiebung l eines Teilchens und seiner Beweglichkeit ergaben, 

 dass für ein langgestrecktes Teilchen l gemessen in der Längsrich- 

 tung des Teilchens {l\) grösser sein muss als senkrecht dazu (Aq). 

 Beobachtungen der mittleren Verschiebungen von Bakterienketten 

 {Bacillus subtüis) mittels des Kardioidkondensors bestätigen diesen 

 Schluss. Unter Anwendung von Formeln für den Widerstand eines 



gestreckten EUipsoids lässt sich aus l die Lochschmidt'sche Zahi 

 N berechnen. Die Teilchen (Bacterien) sind aber keine reinen El- 

 lipsoide. Matouschek (Wien). 



West. G. S. and B, M. Griffiths. The Time-Sulphur Bacte- 

 ria of the Genus Hülousia. (Ann. Bot. XXVII. N^ 105. p. 83— 

 91. 1913.) 



The paper deals with further work on the huge bacterium 

 which the authors described in 1909 (Proc. Roy. Soc. B. Vol. LXXXI). 

 A new and smaller species is described Hülousia palustris having 

 as average dimensions 25 /< X 14,«, whereas the original Hillousia 

 mirahilis averaged 60/^ X 26.u. 



Each organism is peritrichous, C3dindrical and has rounded 

 ends. The protoplast consists of a slender network of meshes 

 within which are large inclusions of amorphous calcium carbonate, 

 and smaller granules of sulphur which are located in the threads 

 of the network occupying the interstices between the globules of 

 calcium carbonate. 



