( 158 ) 
culture” in broth gelatin is made, with 0,1°/, KNO,, after two or 
three days the gas bubbles will appear over the whole length of the 
tube, and herein this species differs from B. vulpinus, where the gas 
bubbles originate at some distance from the meniscus only. 
I will finally make mention of an instructive experiment I performed 
with B. stutzeri. Some garden soil was mixed with tapwater with 
0,05 °/, K,HPO,, and a thin layer of this mixture in an ERLENMEYER- 
flask exposed to a temperature of 25°C. Under these circumstances 
the production of nitrate becomes very marked after two weeks. 
If now the whole content of the ERLENMEYER flask is poured into a 
stoppered bottle, which thereby is quite filled, whilst B. stutzeri, is 
used for infection, soon a development of gas sets in and the nitrate 
disappears completely. Hence it follows that according as the air 
enters our culture liquid well or not, nitrification or denitrification 
may occur. This is quite in accordance with older experiences 
described by ScHiorsine (le) in regard to the soil in general. 
4. Accumulation of Bacillus denitrofluorescens n. sp. 
SEWERIN (I. ¢.) found in 1897 that B. pyocyaneus belongs to the 
denitrifying ferments. But the group of fluorescents proper was long 
fruitlessly examined as to their denitrifying power, first by LEHMANN 
and NeUMANN and afterwards by Weissenpere (I. ¢.). In 1898 KinneMann 
isolated for the first time a denitrifying bacterium, which liquefied 
gelatin and fluoresced. 
Though in my experiments [ often obtained fine cultures of a 
similar species, I did not succeed in finding a satisfactory accumulation 
experiment for it. On the other hand I found such an experiment 
for a non-liquefying fluorescent Bacillus, which I named B. denitro- 
Huorescens. 
The culture liquid for the accumulation of this species is: 
Tap-water, 2 °/, calcium-citrate, 1°/, KNO, and 0,05 °/, K,HPO,. 
In a bottle of 50 Cem. capacity, 1 to 2 gr. fresh garden soil is 
put; it is then quite filled up with the culture liquid, in the way 
described under B. stutzeri. The culture is made at 25° C. 
When sowing on broth gelatin the 2"¢ or 3"¢ transport, successively 
kept in the same culture medium, [always obtained cultures containing 
almost exclusively colonies of that species. 
In horse-dung, canal water and sewage water, I also observed this 
bacterium, but it is with more certainty to be isolated from soil. 
In exterior appearance of the colony this species differs in no 
respect from one of the most common fluorescents, characterised by 
