( 691 ) 



cultures of tlio Iviiow niiiU'i-ohic haclci'ia lliis coinponjid is alwavs 

 (Iccolorisi'd. We iIicitIoi'c (mmiic Io Ilic (•oiicliision, thai llio harteriuiii, 

 wliifli causes llie deiiili-ilicalioii of cellulose, does not «irow on the 

 used uulrieiit uiedia, or else, urow iiiii- tlier(\ loses iniuiediatelv its 

 deuitrifviuii- projierties. 



If jiow we compare the hvdroux'u and iiiclhaiie iei'uieutatious with 

 tli(^ dejiitrifviuu' pi-ocess we tiud tho followiiiu- points of dilfei-eiice. 



J^^ 111 the liydro.ueu or methane fermeutalioji the liberated gaseous 

 products are carbon dioxide ajid hvdrogen, oi- carbon dioxide and 

 methane. 



2"^^ To those fermentations chalk must be added to neuti-alise 

 the formed butyric and acetic acids, whilst in our case the saltpetre 

 yields potassium carbonate and jio volatile acids can l)e detected. 



3'^. Those processes take place in a medium wherein sulphates can 

 be reduced to H^»^ iii^^l therefore niethylene-blue is decolorised. In niv 

 eA[)eriments such a reduction of sulphates is quite out of the <piestion 

 as long as traces of nitrates and nitrites are still j)resent. 



4*'!. The methane and hydrogen fermentation are caused by 

 coinparali\ely large, well characterised spore forming organisms, our 

 denitritication l)y very small bacteria, forming no spores. 



The Nelocity \vith which cellulose disappears during the denitri- 

 fication is about the same as in the methane or hydrogen fermenta- 

 tion of this substance. In a volume of 500 c.c, I succeeded in 

 completely dissoh'ijig 8 grams of cellulose all but a few fibres, bv 

 means of 3(5 grams of KNO.,, in a month's time. The (piantitv of 

 KNO., thcMu-etically required amounts to oidy 24 grams, but in mv 

 experiments a portion of the nitrate was lost in the exi)elle(l li(piid 

 and, therefore, more Jiitrate was re(piired. Hy means of the hydrogen 

 fermejitaticm, (Jmkli.vnski succeeded in dissolving 41 .6 grams of cellulose 

 contained in a volume of 3 litres in 3\/.^ months, and about 12 grams 

 in a volume of 1 litre in 5 months, which Aelocities agi'ee with the 

 values found by me foi- the denitritication. 



Notwithstanding the possibility of denilrilication of saltpetre under 

 the intluence of cellidose. in the preseiice of this substance niti'ilicalion 

 of ammonium salts ami nitrites can [)roceed without iideri-u|)tion. 

 This has already been showji by Omelianski '), who cultivated the 

 nitrite fei-ment on paper. We also observed nitrification of ammonium 

 salts and nitrites, when a \ei-y small (piajitity of cellulose (about 



-) Kleinere Milteilungeii liber Nitrifikationsmiki-obeu I, Cuiilrbl. f. Bakt. Abt. H, 

 Bd. 8, 1902, S. 785. 



47 



Proceediuga Royal Acad. Amsterdam. Vul V. 



