10 Transactions of the ee 
The experiments with grape “must” had to be made chiefly 
with English hot-house grapes, and as these were gathered in the 
months of December and January, the percentage of glucose was, 
as might have been expected, low; but, as in the case of the malt 
extract, the percentage was increased to the required poimt by the 
addition of pure glucose. 
In the fermentation of grape “must” the chief enemy to be 
encountered is the development of mould spores, which, when once 
established, affect the flavour of the wine, and in many instances 
render it unfit for use as a beverage. 
As an illustration of this a sample of wine was made from English 
hot-house grapes, and it would have been a very fair sample con- 
sidering the conditions under which it was made, were it not that 
it possessed a musty odour. On the second day after the juice was 
placed in the chamber for fermentation, a white mould, Ozdiwm 
Tuckeri, formed on the surface, and attempts were made to remove 
it, but in vain, as it rapidly diffused itself throughout the juice. 
On the following day the yeast cells made their appearance in great 
numbers, and they soon took possession of the field and rapidly 
suppressed the further development of the mould on the surface. 
It is true that the ferment afterwards was never pure, but still the 
wine yeast cells continued to work until they had produced upwards 
of 17°68 per cent. of alcohol. 
The grape ferment according to my observations is extremely 
pure and homogeneous in character, and if the conditions are 
favourable for its growth and development it does its work well. 
It works with great steadiness and possesses a degree of persistence 
which does not belong, at least so far as I have seen, to the beer 
ferment. 
In most of the wine fermentation experiments the husks were 
nearly all fermented with the juice, and everything was adopted 
which was thought would add to the fermentative power of the 
“must.” In one instance the percentage of glucose was made up 
to about 36 per cent., and the juice was placed for fermentation in 
a chamber at a temperature of 65° Fahr. On the fourth day fer- 
mentation was visible, and on the tenth day 10°20 per cent. of 
alcohol had been generated; on the twenty-third day 18°54 per 
cent. ; and at the end of ten days more the percentage had increased 
to 18°65 per cent., which is the highest pomt that has been reached 
in natural wine fermentations. The cells, notwithstanding the 
amount of work which they had performed, were even at this point 
bright and globose, and maintained their entirety. 
A sample of these exhausted cells was taken a few days ago 
from the residue of a sample of the wine, and their present appearance 
after the lapse of five months will be seen on Plate LV., Fig. 10. 
