( 62 ) 
nitrate or the nitrite, and not from the concerned organic compound. 
With uric acid there was reason to suppose that this could be 
otherwise, as perhaps the amiao groups might react in the feebly 
acid medium with the nitrous acid and thus per molecule of nitrate 
two molecules of nitrogen ‘ should escape. Quantitative tests have 
however shown that this was neither the case here. 
The same denitrification experiment being repeated at 37°, B. pyo- 
cyaneus was obtained in the winter of 1907—1908. When this 
bacterium was not present in the soil, as in 1909, the denitrification 
remained feeble, 37° being too high for B. Stuzeri, which is then 
also the originator of the gas. 
•4. Fermentation of uric acid by an anaerobic. 
In the same way as in the preceding case, stoppered, 100 cM.* 
bottles were used for these experiments; they were filled with 1 G. 
of uric acid and further with tapwater to which 0,1 % kalium- 
phosphate had been added. 
For the inoculation I took garden soil containing carbonates, from 
which by the free uric, acid some carbonic acid evolves. This slight 
gas production however soon ceases. Canal mud, too, served well 
as inoculation material. With heath soil adhering to Erica, roots, the 
process was slower and a greater quantity of inoculation material 
was wanted to bring about a good fermentation. 
Ihe most favourable temperature lies at about 35°; at 45° the 
fermentation is less energetic. Temperatures below 30° are also less 
Aft* * en ^ ermenta ^ on does not always go on regularly. 
At er a day’s cultivation the first traces of gas are already observed, 
an en it rapidly increases in quantity. But when it has reached a 
cerain eight the fermentation strongly relaxes. This relaxing could 
»o e ascribed to want of uric acid, as by the murexidreaction it 
° 0U . . ^ et * n abundance be indicated, both in the fluid and in the 
precipitate. 
tion "h'l SUpp1 ^ of uric acid somewhat accelerate the fermenta- 
> u as was to be expected, gave no positive amelioration. 
le great concentration of the ammonium compounds from the uric acid 
I ° Un cause °f the abatement. This noxious influence was 
(MefTpo 6 7?^ b ‘ V the Edition of neutral magnesium phosphate 
Der T, ) . * k- TWS Salt ’ with difficulty soluble in water (0.01 gr. 
mafn V C0 “ bines Wlt h the ammonium carbonate to ammonium- 
addition % P 10s P bate ?hence the reaction continues neutral. That the 
0 magnesium phosphate really has this result is at once 
