496 Green . — The Alcohol-producing 
the other hand, there was a copious escape of gas, and the 
mercury showed a permanent displacement of i*5 inch. 
It is interesting to note from this experiment that whatever 
gave rise to the evolution of gas was associated with the 
precipitate to a very large extent as soon as the latter was 
formed. The precipitate did not, however, remove from the 
solution all the gas-generating power, as the filtered liquid 
continued to give off gas, though in greatly reduced amount. 
The evolution of gas in these two flasks was still going on 
at the end of a week from the beginning of the experiment. 
I then drew the gaseous contents of both flasks through 
baryta-water by means of an aspirator, and, as I expected, 
there was an immediate formation of barium carbonate, 
showing that the gas was C 0 2 . 
I then distilled the contents of the flask, and found the 
liquid to have a specific gravity corresponding to the presence 
of about i*5% of alcohol. The presence of the latter was 
confirmed by the iodoform reaction. The original extract, 
as prepared from the yeast, contained about *3 °/ o of 
alcohol, so that during the fermentation rather more than 
1 °/ o of spirit was formed. 
The second extract, which was prepared by the heavier 
pressure as stated above, measured only about 15 cc. I filtered 
this through a porcelain filter under pressure and mixed it 
with sugar-solution, as in the other case : but instead of fixing 
a manometer to the flask I attached the latter to an arrange- 
ment by which the evolved gas was led through a tube 
containing calcium chloride to a set of potash-bulbs, so that 
its weight might be ascertained. Escape of water from the 
flask was guarded against by filling the connecting arm with 
sterilized cotton-wool. It gave off gas much more slowly 
than the liquid in the other flask, but there was still a notice- 
able activity. The flask and the bulbs were both weighed at 
the commencement of the observation, and again as the 
experiment proceeded. There was a continuous diminution 
in the weight of the flask, and a corresponding gain in that 
of the bulbs. 
