AN ALL-GLASS NITROGEN APPARATUS 



E. R. ALLEN 



Visiting Investigator, Missouri Botanical Garden 

 Associate in Biochemistry, Washington University School of Medicine 



an y B. S. DAVISSON 



First Assistant in Soil Technology, 

 Ohio Agricultural Experiment Station, Wooster, Ohio 



The necessity of refinsd analytical methods is apparent to 

 any one who has given serious consideration to the problem 

 or problems in certain phases of plant metabolism. This 

 need is especially felt in the problems of nitrogen fixation by 

 the lower forms of plant life. Helpful suggestions may be 

 obtained from the nitrogen methods used in the field of 

 animal biochemistry, yet these methods are usually not 

 directly applicable without more or less revision with a view 

 to obtaining greater accuracy even at the expense of con- 

 venience and ease of manipulation. This is illustrated, for 

 instance, by the nitrogen method proposed by Davis 1 while 

 working on the problem of nitrogen fixation by fungi in the 

 laboratory of Professor Duggar. This method may be con- 

 sidered as intermediate', in general features, between the 

 ' l micro " methods of Folin and the standard methods employ- 

 ing a bank of block tin siills and necessary additional devices. 



Continuance of the experimentation described by one of 

 us 2 in this laboratory and in the Wooster laboratory gave 

 rise to an apparatus which we feel merits recommendation to 

 other workers in similar fields. Its features are: (1) elim- 

 ination of rubber stoppers and connection; (2) efficient scrub- 

 bing of the entrained alkali from the steam; and (3) the use 

 of Pyrex glass, which does not yield an appreciable amount 

 of alkali to steam or boiling solutions. 3 



1 Davis, A. R. A note on Jie adaptability of the Folin micro-Kjeldahl ap- 

 paratus for plant work. Ann. Mo. Bot. Gard. 3 : 407-412. pi. 7. 1916. 



•Allen, E. R. Some conditions affecting the growth and activities of Azoto- 

 bacter chroococcum. Ann. Mo. lot. Gard. 6 : 1-44. pi. 1. f. 1-2. 1919. 



8 Davisson, B. S. Ammonia und nitric nitrogen determinations in soil extracts 

 and physiological solutions. Joiir. Ind. and Eng. Chem. 10: 600-605. f. 1-8. 1918, 



Ann. Mo. Bot. Gard., Vol. 6, 1919 



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