424 ON THE JUICE OF THE SUGAR-CANE. 
above that obtained by the direct notation before the acidulation of the 
juice. The rotatory power of levulose peculiar to the cane, without 
doubt stronger than that of sugar interverted artificially, is quite sufficient 
to explain what takes place in the first case ; but in the second case, it 
.becomes necessary to admit that there exists in the juice a substance 
with a rotation to the right, which substance is something different 
from crystal lizable sugar, and which is not susceptible of modification by 
aeids. 
Would not such a substance be the first state into which levulose enters 
in order to become crystallizable sugar ? Without attempting to substi- 
tute hypotheses for facts, and theory for observation, it seems right to 
submit such a question as this, when we remember, as I have clearly 
established already, the predominance of liquid sugar in the cane, the 
juice of which has not as yet been completely elaborated ; the gradual 
diminution of this substance in proportion as crystallizable sugar aug- 
ments ; and finally its continuance so long as vegetation is maintained, 
and its disappearence when vegetation becomes nearly stationary, and 
its reappearance when vegetative vigour recommences. Unless we make 
the absurd admission that the uncrystallizable sugar which, under similar 
circumstances, exists on the juice of the cane in its full vigour of growth 
is simply a product of change similar to that which fermentations and 
acids cause crystallizable sugar to undergo, it is difficult to regard in any 
other way than I have done, this transformation the phases of 
which IJiave described. Aaccording to this hypothesis cane sugar, that 
which definitely speaking, is found in its totality in the ripe cane, would 
not originate in the midst of the liquid which moistens the different 
parts of the vegetable tissue ; but it would be gradually formed at the 
expense of another body which, being greatly like it, would com- 
plete its modification under the double influence of vegetation and sun- 
light. 
6. To resume : I may state that the sugar originally existing in the tis- 
sues of the cane differs in many respects from what is extracted from 
them in the full development and maturity of the plant ; and that it 
may readi*y be admitted that the crystallizable prismatic sugar is the de- 
finite result of an operation "which takes place in the formation of glu- 
cose ; the latter however, is the lost term of an operation which can be 
produced artificially, while the former on the contrary, can only origi- 
nate from the vegetable organisation and under the influence of the vital 
forces. 
The processes I have followed in order to determine the nature and the 
quantity of sugar contained in cane-juice are those which at the present 
day exhibit the greatest precif ion, and which are generally employed 
under such circumstances. In having thus only followed the ordinary 
methods, I am thereby enabled to spare my readers a description of de- 
tails which are familiar to scientific men. There is, however, a reagent 
