ON THE JUICE OF THE SUGAR-CANE. • 471 
Aii idea may be formed of the augmentation of this substance when 
concentrated in the syrups, by reference to experiments I have made. 
From these it will be seen that the figures representing it follow 
a rapid progression, and are six or seven times higher for syrups in 
the third stage than for the " (Jlairce " at 22° Beaume. They also 
equally show the increasing progression of the saline matters peculiar 
to the different syrups. These two kinds of substances are not always 
sufficient, however, to explain the resistance to crystallization exhibited 
by syrups produced under certain circumstances. There is a cause of 
very different activity, and that is the presence in these saccharine 
liquids during manufacture of a quantity of glucose more or less great, 
a substance which is the stumbling-block of colonial industry, and the 
source of the chief difficulties against which the sugar-manufacturer 
has incessantly to struggle. I have shown in the clearest manner that 
the liquid sugar was not, as generally thought, a product of the alteration 
of the cane, but a really radical portion of its organisation, and that 
such sugar was more abundant in proportion as the plant was furthest 
from the period of its development. I have also demonstrated that if 
the body of the ripe cane contained only traces of it, the head of the 
cane, on the contrary, contained a notable proportion ; and that what- 
ever tended to produce abnormal vegetation, had the effect of causing 
the re-appearance of this substance in the cane. We may, therefore, 
conclude from this fact that levulose is always present in the juice 
which is generally manufactured, and that its presence is greater in pro- 
portion as the canes operated on are less ripe, have grown in a damp 
soil, and have been cut at a sectional point nearer to the insertion of 
the green leaves. 
The presence of interverted sugar in the juice being admitted, it is 
easy to understand the first difficulty which presents itself, and the 
almost absolute impossibility of effectually overcoming it. For how 
can we avoid so injurious an action as that of the lime on the levulose 
which, at the boiling temperature and in contact with this alkali, gives 
rise to those black products of glucose, the presence of which produces 
such decided change in the colour of the juice, and in the quantity of 
the sugar obtained from it ? How can we avoid so real an inconvenience 
and at the same time stop the too great tendency which these juices 
exhibit to produce during boiling a considerable quantity of glucose ? 
The alkalinity of the liquid would, without doubt, fix a limit to 
this rapid transformation ; but would not this very alkalinity, in 
similar cases, produce consequences more fatal than the evil to be 
subdued ? 
Lime, the usefulness of which is incontestable, but the importance 
of which we have been disposed to exaggerate, cannot be employed in 
excess without becoming the cause of one of the most injurious modifi- 
cations which the juice undergoes, and which has for its immediate 
