228 EXPERIMENT STATION RECORD. 



ing tbe conclusion that this reduction is due to an aerobic ferment 

 brought in with the seeds, which develops at the expense of the organic 

 matter extracted from the seeds by the water used. These reducing 

 agents not only utilize the oxygen dissolved in the water, but also that 

 of the nitric acid. 



In continuation and extension of the work of Breal, the author 

 undertook (1) to determine whether nitrates are reduced under free 

 access of air and to what form are they finally reduced, and (2) to iso- 

 late the ferment from the plant and study it in pure cultures. The 1 

 results obtained were as follows: 



(1) The reduction of the nitrates in the germination of seeds (Gram- 

 ineae, Cruciferae, and Leguminosae) to nitrons acid and ammonia is due 

 to microorganisms. 



(2) A denitrifying aerobic microorganism is associated with the 

 seeds and lives at the expense of the water-soluble substances of the 

 seed coat and the chaff. 



(3) This aerobic microorganism can be isolated by the ordinary 

 bacteriological methods and occurs in fresh cultures almost exclusively 

 in the form of a Diplo bacillus, very quick in its movements, and 

 quickly liquefying gelatin in plate cultures. 



(4) In artificial cultures it may live in the presence of only dextrose 

 and nitrates (besides inorganic salts), although an addition of a small 

 quantity of nitrogenous substances (bouillon) is very favorable to its 

 growth. 



(5) The reduction of nitrates in artificial media is so rapid that it can 

 only be explained on bacteriological grounds. 



(6) The reduction of nitric acid in pure cultures of the organism 

 passes through the nitrous acid stage, but continues until free nitrogen 

 is formed. 



(7) That the organism is aerobic is proved very clearly by its growth 

 in various nutritive media and by its feeble growth in the absence of 

 oxygen. 



(8) On gelatin with nitrates it grows for a long time without liquefy- 

 ing. Liquefaction takes place after 20 days, beginning from the top 

 and slowly proceeding into the depth of the media. This peculiar 

 growth gives reason to suppose that denitrification is a chemical 

 process. 



(9) A complete account of the products of the life activity of the 

 bacillus is impossible as yet.— p. fireman. 



Bacteria of horse manure and their physiological role in the 

 decomposition of the manure, Severin (Trudi Imp. Voln. Econ. 

 Obshch, AJcklim. Zhivotnikh i Rastenii, 5 (1895), pp.— ). — The author suc- 

 ceeded in separating 26 species of bacteria from manure, of which 2 

 were aerobic and 2 anaerobic. Of the latter one proved to be a micro 

 organism capable of producing tetanus. Parallel experiments wen 

 carried out on the decomposition of manure, on the one hand, withon 

 the participation of microorganisms under the iufiueuce of air alone, 



: 

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