ON FALSE MANNA. 
209 
the shade of brown is much deeper, in some places being nearly 
black. The whole surface is rough and irregular. The fracture 
is equally rough and irregular, exhibiting many crystalline points, 
and here and there well defined crystals of cane sugar. The 
mass is made up of small compressed and flattened pieces that 
bear no inconsiderable resemblance to preserved citron. Both 
water and alcohol (sp. gr, -335) dissolved about ninety per cent ; 
water taking up a somewhat larger proportion than alcohol. The 
residuum is tasteless and odorless, and has a pectinous pulpy con- 
sistence after the action of water. 
Prof. Wm. Procter, Jr., made some experiments with a view of 
determining its chemical nature, which, although not pushed so 
far as to decide on the character of the bitter principle, were 
sufficient to satisfy him, that the so-called manna does not con- 
tain any mannite, the saccharine constituent of all mannas, but 
that, on the contrary, its sweetness is owing to the presence of 
a large proportion of cane sugar with a little glucose. 
A portion was boiled in alcohol (sp. gr. -835,) strained while 
hot and set aside to cool and crystallize. At the expiration of 
60 hours no crystals had formed. Had mannite been present, 
delicate crystalline needles would certainly have been deposited 
prior to the expiration of this period. 
A second portion was dissolved in water, strained and concen- 
trated to a syrupy consistence. Upon standing, well defined ob- 
lique, four-sided, transparent crystals were deposited in great 
abundance. These crystals were charred by sulphuric acid, but 
slightly affected by a boiling solution of caustic potassa, and when 
heated in an alkaline solution of sulphate of copper, afforded 
little if any evidence of grape sugar, whilst the brown mother 
liquor was blackened by boiling potassa solution and readily pre- 
cipitated oxide of copper when the copper test was applied. No 
therapeutical experiments were made, inasmuch as the bitter 
after taste would preclude its use even as a substitute for fat 
manna, my object being simply to expose a gross adulteration. 
