Memoir on the Saccharine Diatetes. 101 
grammes of water; we adapted to the neck of this flask a 
tube fixed under a flask full of water ; the temperature being 
then raised to 18 degrees, the experiinent was left to itself. 
Some hours after the contact took place between these sub- 
stances a motion was evinced in some parts of the liquor, 
which soon became general: plenty of solid flakes, which 
gave birth to a great number of gaseous bubbles, were raised 
to a considerable height; these bubbles rapidly passed into 
the vessels full of water, but the flakes fell back to the bot- 
tom of the flask, and, giving birth to new bubbles, they: 
again ascended to be once more precipitated. This phzno- 
menon, which took place for three days, announced a very 
active fermentation, and, consequently, the presence of a 
great quantity of saccharine matter: in fact, more than thir- 
teen pints of pure carbonic acid gas were liberated; the li- 
quor was very alcoholic, and contained nearly 48 parts of 
alcoho] at 40 degrees ; evaporated to dryness, only 23 parts 
of extract were obtained, formed of three parts of sea salt 
and twenty parts of a viscous brown matter. 
We know that 100 grammes of sugar produce 12 gram- 
mes of a similar residue, 56 of alcohol, and 36 of carbonic 
acid. Thus the substance drawn from diabetic urine yielded 
by fermentation the same products, and almost in as great 
quantity, as pure and finely crystallized sugar; and if we 
add, that it acts like sugar with the nitric acid, eae and 
the other reagents, we must regard these two sut 
being in some measure precisely the same. 
We ought, however, to recollect that it is scarcely sweet, 
at least much less so than sugar. It may be thence con- 
cluded, 1st, That, as has been long suspected, there are dif- 
ferent species or varieties of sugar, the differences being so” 
striking as now to render certain what before was only pro- 
bable. But as the taste only is not a certain criterion of the 
saccharine principle, it becomes necessary to examine if, 
among the substances which have hitherto been confounded 
with sugar on account of their taste, there are not some of 
them which differ essentially from that substance. 
For this reason we were led to examine manna. Our first 
care was to mix it with ferment and water at the tempera~ 
G3 ture 
tances as 
