188 Recent Imjprovements in Cider and Perry Malcinrj. 
scopic fungus, named Saccharomyces pastorianus^ after tlie dis- 
tinguislied Frencli savant M. Pasteur. Like most organised 
beings it lives by absorbing oxygen from the air, but being 
unable to obtain more than a very small quantity of that gas 
in the liquid in which it is immersed, it obtains the oxygen 
from the sugar, and in decomposing the sugar sets free more 
oxygen than it requires. This free oxygen unites with the 
- carbon and hydrogen present, and forms the various products 
of the fermentation. The yeast-plant is not a product of the 
fermentation, but the cause of it, the plant, as above stated, 
being always present upon the skin of the various fruits used. 
Having thus considered the only fermentation which the 
cider-maker wishes to see, we will describe the process which he 
will have to carry through to a successful issue. In this, great 
care will have to be taken with the temperature of the barn or 
cellar in which the fermentation is carried on. If possible, the 
temperature should be sustained at from 55° to 60° Fahr., not 
letting it fall below 50° or rise above 75°, as in both cases the 
operation will cease. Should there be any tendency to fall, the 
temperature can easily be raised by means of a small portable 
stove, with a fire in it, which is the method adopted in France. 
Supposing every condition favourable, in about a week fermen- 
tation will have ceased and the liquor will be fine, having on 
the top a thick floating mass of skin and pulp, and the bottom 
a thick ropy mass, being in the condition which is known as 
" lying between the two lees." This is the favourable moment 
for " racking " it, and the operation is best performed with a 
siphon, the thick portion at the bottom being filtered clear 
through proper filtering bags and added to that already drawn 
off. The cask into which it is racked must be perfectly clean 
and free from any smell whatever, and afterwards the tempera- 
ture be kept low. A considerable ullage should be left in the 
cask in case secondary fermentation should set in, when the 
whole operation must bo repeated. 
The entire operation is a crucial one, and will test the cider- 
maker's watchful cai'e and management to the utmost, for the most 
skilful operators cannot always command success at once, many 
causes operating against it. The season may have been bad, 
and the fruit not ripened properly ; the fruit may have fer- 
mented in the heaps, become frost-bitten, or rotten; it may be 
])oor and watery ; the tcMuperaturo may be too low at the time 
of making and retard fermentation, or even stop it altogether, 
or it may be too high and carry it through too quickly, although 
with proper buildings tliis is to a very great extent under the 
maker's control ; lastly, there may have been a want of cleanli- 
new« iil t-ho vessels or impleineuts i|sed. This latter may b(? 
