137 
original sample of gas. Pure oxygen was used in the explosion, and the 
excess after it could be absorbed and a residue, if any, measured. In 
all cases there was a residue of from one to five cubic centimeters, hardly 
enough for proof of the presence of nitrogen. 
In order to prove the presence of nitrogen in the residue, a large fer- 
mentation tube was procured and a culture made in this, using the neces- 
sary precautions. Smith’s fermentation fluid, +1% of glucose, was used. The 
gases, CO., CO, H and O, were absorbed as described before. The res- 
idue, amounting to some 20 c. ¢., was kept in a pipette over water; 10 ¢. ¢. 
of this residue was transferred to a eudiometer provided with platinum 
electrodes and mixed with 22 ¢. c. of oxygen prepared from the electro- 
lysis of water. This mixture was sparked. In the course of three hours 
the volume showed some signs of diminution, and after six hours 
the volume had been reduced to less than half. The current was turned 
off and the gas allowed to stand for 24 hours, with no practical change in 
results. 
The contraction in volume of the gas when sparked with oxygen 
showed the presence of nitrogen in the formation of an oxide of nitrogen 
which was soluble in water. 
Micro-OrGANISMS IN Fiour. By CARLETON G. FERRIS. 
Flours have been studied from the chemical standpoint with consid- 
erable care, but comparatively little has been done as regards investiga- 
tion from the bacteriological standpoint. Although the chemical side of 
the question has been considered the most important, as it undoubtedly is, 
there are certain changes occurring in dough made from chemically pure 
fiour which cannot be attributed to the chemical side of the question. For 
example, bread made from a flour which chemically contained a proper 
quantity of gluten, ete., may be spoiled. The point might be raised by some 
that the bad bread was not the result of using a certain flour, but that the 
micro-organisms present were found in the water used and in the sur- 
rounding air, or possibly from an impure yeast. Experiment has proven, 
however, that bad bread can be obtained even when sterilized, distilled 
water and pure yeast are used. As the growth of bacteria does not com- 
mence in the dough until nearly all fermentation has ceased, it is 
reasonable to assume that the changes in the dough and in the 
