PRODUCED BY BODIES ACTING BY CONTACT. ll 
acid upon cane sugar in crystals. The sugar which is procured 
by adding the yeast of beer to a solution of cane sugar appeared 
to differ from grape sugar. I have not succeeded in obtaining 
it crystallized, and it deflects polarized light much less than an 
equal quantity of grape sugar. Its formation is very remarkable : 
it is owing to a substance mixed with the globules of ferment ; 
it is the aqueous solution of this matter which determines the 
conversion of cane sugar into this new sugar. For this reason 
it is that fermentation takes place much more slowly in a solu- 
tion of cane sugar, when washed yeast is used instead of com- 
mon yeast. Common yeast excites fermentation as quickly in a 
solution of cane sugar as in a solution of glucose. 
This kind of sugar differs, moreover, from that which is ob- 
tained by melting cane sugar, 
By melting cane sugar at a temperature of 106° it becomes 
completely deliquescent, dissolves in absolute alcohol, ferments 
when in contact with yeast, and exercises a much smaller influ- 
ence upon polarized light than grape sugar. 
Cane sugar does not crystallize again after having been melted; 
but if, on the contrary, it is melted with water, taking the pre- 
caution not to raise the temperature above 154°, it solidifies on 
cooling, and a vitreous mass, composed in great part of cane 
sugar retaining water mechanically inclosed,is obtained. This dis- 
solves the particles of sugar, one after another, and deposits them 
in the state of crystals; for an amorphous body is more soluble 
than a crystallized one; the entire mass passes into a crystalline 
state. It is very easy, by breaking a stick of such sugar, to de- 
tect the presence of the water, which is found especially toward 
the centre and between the crystals. It is possible that the 
sugar may be identical with that obtained by maintaining for a 
long time a solution of cane sugar at 110°, and which, according 
to M. Fensky, exercises no action on polarized light. Perhaps 
it is also identical with that which M. Péligot and M. Mulder 
have obtained by boiling cane sugar for a very long time with 
dilute acids, and which, according to. those observers, does not 
crystallize. 
All chemists are agreed with regard to the transformation 
which glucose and other kinds of sugar undergo during fermen- 
tation: it is generally admitted that a third of the carbon of the 
sugar is converted into carbonic acid, whilst the other two-thirds 
unite with hydrogen and oxygen to form alcohol; thus, for every 
