Monthly Microscopical 
ee Jay Loe Royal Microscopical Society. 9 
hardly refer to the difficulty which was experienced in obtaining a 
pure healthy fermentation from a malt extract prepared at this 
temperature, although the infusion was maintained at that tempe- 
rature for upwards of three hours, and the addition of 30 per cent. 
of glucose operated as an antiseptic. 
The most successful malt wort fermentation was one in which 
the glucose, including that naturally present in the malt extract, 
amounted to over 36 per cent., and the fermentation was conducted 
at a temperature ranging from 63° to 70° Fahr. No fermentation was 
visible until the sixth day, when a number of hazy cells, which in- 
dicate the commencement of fermentation, made their appearance. 
Soon after this the fermentation began to be brisk, and by the ninth 
day 10°96 per cent. of alcohol had been generated, or within 1°35 
per cent. of the quantity produced in the same time in the cane sugar 
solution by the addition of yeast. Now this fact, is very interest- 
ing, as it serves to show the great facility with which glucose, as 
compared with cane sugar, is resolved into alcohol and carbonic 
acid gas, and to indicate the large additional expenditure of force 
which must be required to effect the two transformations in cane 
sugar by the fermentative process. 
From the ninth day the fermentation began to abate; in the 
three days following 2°83 per cent. of alcohol was produced, and in 
the next sixteen days 2°60, making altogether 16°35 per cent. of 
alcohol, which is the highest amount that has been reached in the 
fermentation of malt extracts prepared in the way described. It 
should be noted, -however, that in this case the fermented liquid 
contained over 7 per cent. of glucose, and that it is probable if the 
proportion of glucose had been less a higher percentage of alcohol 
might have been produced. 
It may be proper to mention that from a series of experiments 
it has been found that alcohol and sugar combine to act as an 
antiseptic, and that by increasing the percentage of sugar the 
fermentative power of the liquid is proportionately decreased. It is 
upon this property of their combined action that a less quantity of 
proof spirit is required to be present in liqueur than in ordinary 
wines, to prevent their deterioration. For example, a properly-made 
liqueur wine, containing 20 per cent. of glucose and about 14 per cent. 
of alcohol would be perfectly safe for keeping, or indeed for removing, 
to any part of the world ; butif the wine contained only 14 per cent. 
of glucose, to render it proof against deterioration the proportion of 
alcohol would require to be increased to about 17 per cent. 
A specimen of the exhausted yeast cells taken from the fer- 
mented wort in which the highest percentage of alcohol was pro- 
duced, will be seen on Plate LV., Fig. 9; and it will be noticed that 
the cells are very granular and much aggregated, properties which 
are to some extent characteristic of the exhausted malt ferment. 
