OONDITION OF THE JUICE IN THE STALK. 205 
9. CONDITION OF THE JUICE IN DIFFERENT PARTS OF THE 
STALK. §S. cane.—In different portions of the same stalk 
the constituents of the juice vary considerably (at least 
in the case of cane grown in Louisiana), and especially 
in the nature of the saccharine products. In Otaheitan 
cane of nine months’ growth, McCulloh found the three 
or four top joints had a sour, astringent taste, promptly . 
staining the knife black with which they were cut, and yield- 
ing but a small quantity of juice, which, by the copper test, 
was found to contain grape sugar, and no starch. Subace- 
tate of lead gave a precipitate of a dark olive color, equal 
in volume to 4 of the entire mixture. 
Three or four joints below these had a slightly sweet 
astringent and acid taste,* of a density of 7° Beaumé; with 
this juice subacetate of lead gave a dense, dark olive pre- 
cipitate, in bulk equal to # of the entire volume of the 
mixture as in the former case—grape sugar was also found 
* The presence of a free acid in the juice of sorghum has induced some 
to infer, without investigation, that the plant contains only grape sugar. 
The fact is just the reverse, as is clearly proved; but that sorghum juice 
is not an isolated example of the fact that in the living plant the pres- 
ence of an acid is not incompatible with the existence of cane sugar, the 
above experiment attests. The experiments of MM. Berthelot and 
Buignet (Comptes Rendus, vol. li. p. 1094), on the ripening of oranges, 
show this still more clearly. They have proved, in a series of accurate 
and laborious investigations, that cane sugar is formed and increases in 
an acid medium. Not only does the citric acid appear not to act in in- 
verting the cane sugar already formed, but it does not oppose the aug- 
mentation of the sugar itself. The orange, both before and after the 
period of maturity, contains both cane and inverted sugar. The weight 
of the latter varies little ; it was first preponderant, but during maturation 
the relations changed, and cane sugar became the most abundant. The 
weight of the cane sugar augments relatively to the total weight of the 
orange. It increases equally, whether compared with the total weight 
of the juice or with the weight of the fixed matter contained in the 
juice.—London Chem. News, 1861, vol. v. p. 117. 
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