324 Transactions. 



The high fat-content was mainly brain-fat, and, as this fat 

 readily emulsifies with water, it could not be readily removed 

 from the liquor ; this article is not now manufactured in this 

 colony. No. 8 was taken from a trial lot of rabbit-extract, 

 and, while this article is not manufactured in New Zealand, 

 its analysis indicates the possibility of utilising this material. 



For permission to publish these results I have to express 

 my thanks to the general manager of the Christchurch Meat 

 Company (Limited), in whose laboratory most of the work 

 was carried out. 



Art. XXIX. — The Fixation of Atmospheric Nitrogen by Nitrogen- 

 fixing Bacteria in Certain Solutions. 



By A. M. Wright, F.C.S. (Berlin), M.Am.C.S. 



[Read before the Philosophical Institute of Canterbury, llth December. 1907.] 



This paper is the record of the work carried out preliminary 

 to soil experiments to determine under what conditions of 

 alkalinity and acidity nitrogen- fixing bacteria will fix atmo- 

 spheric nitrogen. 



A solution of 1 gram each of cane-sugar, ammonium-sulphate, 

 magnesium-sulphate, and potassium-sulphate in 1 litre of water 

 was prepared ; to 10 cubic centimeters of this solution 100 

 milligrams of cotton-wool containing the bacteria were added. 

 This was then rendered acid or alkaline. The degrees of acidity 

 or alkalinity are expressed as parts of calcium-oxide per million, 

 this being the usual method of expressing these results in soil- 

 determinations. 



The experiments were carried out in Kjeldahl digestion 

 flasks. At the end of the experiment it was merely necessary 

 to add mercury and sulphuric acid, and proceed with the nitrogen 

 determination as in other Kjeldahl estimations.* 



Neutral Solution. 



Days. 



II 



:5 .. 



7 

 10 

 14 

 •21 

 28 



* Bull. No. si. Bureau of Chemistry, U.S.A. Dept. of A'gric, p. 152. 



