FRAXINUS OI?NUS. 
erect anthers ; the gerraen is oval, compressed, and supports a short 
cylindrical style, crowned With a notched stigma ; the capsule is 
long, flat, and membranous, and contains a single, fiat, pointed, dark 
brown seed. This is not the only species of ash which produces 
manna. 
Sensible and Chemical Properties. The best Calabrian, 
or what is called the flake manna of commerce, is in oblong, light, 
friable pieces, of a whitish, or pale yellow colour, and somewhat 
transparent ; its taste is sweet, accojnpanied with a peculiarnauseous 
flavour, which it leaves upon tlie tongue. Manna liquefies in moist 
air; dissolves perfectly in water, and also in alcohol, when assisted 
by heat. The alcoholic solution, when slowly evaporated, gradually 
deposits five-eighths of the manna, of a tine white colour, somewhat 
crystalline, light and spongy. The precipitate thus obtained, is 
probably pure manna ; it instantly melts upon the tongue, and has 
an agreeable sweet taste, without any of the nauseousness of manna. 
By further evaporation, one-fourth more is obtained, but less fine 
than the former, by continuing the evaporation, a thick extract is 
formed, which can scarcely be reduced to dryness; this extract, 
^yhich amounts to about one-eighth of the manna operated upon,, 
consists chiefly of foreign bodies, and to these, or some of them, 
manna owes its nauseous flavour. According to Fourcroy, when 
a solution of manna is clarified with the whites of eggs, and suffici- 
ently concentrated, crystals of sugar may be obtained from it; but 
with Dr. Thomson, the experiment did not succeed ; its crystals 
Were always acicular, and with more difficulty formed. 
According to the experiments of Vauqnelin and Fourcroy, the 
manna of commerce consists of four different ingredients ; 1. pure 
manna; 2. a small quantity of common sugar; J?, a yellow matter, 
with a nauseous odour, (to which probably the unpleasant flavour, 
and purgative qualities of manna is owing) ; 4. a little mucilage. 
The proportion of these several substances depends, in some measure, 
on the purity of the maqna operated upon. The pure crystalline 
manna usually constitutes three-fourths of the whole mass. 
Manna, when digested in nitric acid, yields both oxalic and 
saclactic acids, in this it differs from sugar which yields oxalic acid 
only. 
Although the Fraxinus Ornus produces the greatest quantity, and 
the finest manna, it is by no means to be considered as a substance 
peculiar to this tree ; for not only is it obtained from the Fraxinus Ro- 
tundifolia and Excelsior, particularly in Sicily, but many other trees 
and shrubs of different families are known, k certaiu seasoiis and 
