PURIFYING COMMON MANNA. 
47 
suits of which will be cited; but, in the first place it may 
be stated, that the manna of M. Dausse presents itself 
in stalactiform concretions, much resembling natural flake 
manna; that it is deprived if not of the whole, of at least a 
part of the nauseous odour peculiar to this substance. Some 
pieces have the whiteness of recent manna, while others more 
coloured resemble more the manna of two years standing. To 
equal whiteness of both kinds, the purified manna is less 
friable, it becomes more glutinous by trituration, it is also 
more hygrometric. Thus, as states the author in his letter to the 
Academy, flake manna prepared artificially, is completely 
dissolved in water without disturbing its transparency; let us 
observe at the same time that this solution is a little more co- 
loured than that of natural flake manna, that it does not redden 
in the same way litmus paper, a result evidently due to the 
reaction of the free acid of the manna and the small quantity 
of carbonate of lime contained in the animal charcoal used in 
the purification. The purified manna, more soluble in boiling 
alcohol than natural manna, leaves nevertheless a small brown- 
ish coloured residuum, and what is remarkable, contains much 
less mannite. Thus we have obtained from the manna of M. 
Dausse but 44 per cent, of this principle, while the flake manna 
of commerce furnishes 68 per cent. As is manifest, the puri- 
fied common manna, while it assumes the appearance of flake 
manna, contains one-third less of one of its principal elements, 
and as a necessary consequence, the gum and sugar do not 
exist in the same proportions. Therapeutic experiments alone 
can decide the question, to what degree do the two articles, 
differing in the proportion of their component parts, resemble 
or differ from each other in their medical properties. The 
member of the committee who especially undertook this part 
of the examination, has administered the purified manna to 
many patients under his care in the wards of the Hotel Dieu, 
and the following are his results: 
Nine subjects of different ages, constitutions and pathologi- 
cal conditions, took two and a half ounces of manna eacl). 
