824 APPENDIX. 
All the fruits may be used for the same purpose ; a bunch of grapes 
crushed between the hands is sufficient to ferment a large vat of several 
hectolitres, the juice of the sorgho containing naturally a sufficiency of 
azotized matters to cause fermentation to continue naturally after be- 
ing thus started ; a ferment of paste, made of the inner part of bread, 
may take the place of the yeast. In the case where juice largely 
charged with sugar and derived from very dry stalks, (and of course 
almost deprived of those younger parts which yield nitrogenous mat- 
ter) experience a too mild or incomplete fermentation, a little of the 
flour of French rice will be sufficient to give it all the activity desired. 
Once let the movement be established, it is probable that the method 
of continuous fermentation so happily applied to the distillation of the 
beet, and which consists in the constant introduction of a fine thread- 
like stream of sweetened liquid into a vat where fermentation is already 
active, might be adopted, and thus dispense with all anxiety as to the 
procuring of different ferments. This method has the additional ad- 
vantage, that it can perfectly regulate the fermentation, and thus obvi- 
ate, as much as it is possible, the formation of acetic acid. 
It is requisite, in order that the fermentation may be regular, that 
the temperature should be maintained between 18° to 25° centigrade. 
This precaution is especially necessary in the small experiments of the 
laboratory, for which a constant temperature of 25° has always suc- 
ceeded with me. I have made mention of a process of purification based 
upon the use of oak-wood shavings, and which entirely destroys the 
taste of the green matter arising from the crushing of the bark of the 
stalks by the rollers.* I have observed since then, that, if they are 
used in excess, either by too prolonged an ebullition or by increasing 
the proportion of shavings, (which should never exceed 200 grammes 
to the hectolitre of juice,) this method actually opposes the fermenta- 
tion. Weshould therefore give some attention to the proper method 
of employing it, the more, because for distillation the juices obtained 
from the rolling mill are so clear as not to have a disagreeable flavor, 
even when they are put to ferment in their raw state. Perhaps other 
processes, such as the use of white wood and the coal of wood, might 
be successfully employed for the defecation or clarification of juices. 
* See Journal @ Agriculture Pratique, (No. of 25th November, p 420.) 
