THE NITRIFYING PROCESS AND ITS SPECIFIC FERMENT. 
117 
from this bottle No. 4 on July 7, 1888, and on July 12 a very delicate growth in the 
depth and on the surface of the gelatine was observed. On microscopic examination, 
This was seen to be due to very characteristic long and slender bacilli. From one of 
these gelatine-tubes exhibiting this growth two bottles containing sterile aminoniacal 
solution were inoculated on July 12, 1888, and both of these bottles subsequently 
(examined on September 3 and October 1, 1888) nitrified. 
This might at first sight be supposed to afford evidence that the nitrification had 
been caused by a pure growth taken from the gelatine-tubes, but on taking the 
following circumstances into consideration this was seen to bear another interpretation. 
Thus, on July 7th, 1888, two bottles containing sterile ammoniacal solution were 
inoculated from the nitrified bottle No. 4 in the' above series ; already, on July 12th, 
these bottles were found to be distinctly opalescent, and one of them was tested for 
nitrous and nitric acids but with negative results ; on microscopic examination, the 
bottle appeared to contain two different organisms, one a small fat bacillus, and 
the other a long bacillus, much resembling that observed in the gelatine-culture 
mentioned above. Bottles 3 and 5 of the above series, and which had not nitrified, 
were also microscopically examined and found to contain apparently pure growths of 
the short fat bacilli. Bottle 3 was inoculated into gelatine to compare the growth with 
that obtained from bottle 4, wifli the result that the same growth was formed, and 
this, on microscopical examination, was seen to consist of the same long bacillus. 
Somewhat later (July 15, 1888) the gelatine tube, inoculated from bottle 4, began 
developing a second and less conspicuous surface growth tham that which first 
appeared, and this second growth, on microscopic examination, was found to consist of 
the short fat bacillus. Thus, both the long and short bacilli wei'e obtained from bottle 
4, which had nitrified, they were also both obtained from bottle 3, which had not 
nitrified ; and, therefore, the only probable conclusion was that neither of these 
organisms were connected with the nitrifying process. 
The nitrification in bottle 4 must, therefore, have been caused by some tlfird 
organism which had not grown in the two gelatine-tubes inoculated therefrom, and 
the nitrification induced by inoculating these gelatine-tube growths, as described 
above, must have been due to the transference of some of this third organism along 
with the visible growth. This is the more likely as the inoculation from the gelatine- 
tubes into the bottles was made only five days after the inoculation (July 7, 1888) 
of the gelatine-tubes themselves from bottle No. 4 ; and, on subsequently (September 3, 
1888) endeavouring to cause nitrification by inoculating from these gelatine-tubes, the 
attempt failed, probably because the growth had increased, and there was, therefore, 
less probability of carrying any of the original matter introduced into the tube 
with the inoculating needle. 
Although the nitrification occasioned by inoculation from the gelatine-tubes referred 
to above, could certainly not have been caused by a pure growth, still there was every 
reason to believe that the bottles which had thus nitrified, would contain a less admix- 
