which is collected in baskets, and goes under the name of manna grassa, is put in a dry place, because 
moisture and a damp atmosphere will soon dissolve it again. 
“ This first kind is often in large irregular pieces of a brownish colour, and frequently is full of dust 
and other impurities. But when the people want to have a very fine manna, they apply to the incision of 
the bark thin straw, or bits of shrubs, so that the manna, in coming out, runs upon those bodies, and is 
collected in a sort of regular tubes, which give it the name of manjia in cannoli, that is, manna in tubes ; 
this second kind is more esteemed, and always preferred to the other, because it is free and clear. There 
is, indeed, a third kind of manna, which is not commonly to be met with, and which I saw after I left 
Calabria; it is very white, like sugar; but it is rather for curiosity than for use. The two sorts of manna 
already mentioned undergo no kind of preparation whatever before they are exported ; sometimes they are 
finer, particularly the manna grassa, and sometimes very dirty and full of impurities ; but the Neapolitans 
have no interest in adulterating manna, because they always have a great deal more than they export ; and 
if manna is kept in magazines, it receives often very great hurt by the southern winds, so common in our 
part of the world. When the summer is rainy, the manna is always scarce and bad.” 
Manna likwise exudes spontaneously and concretes into granules; it is known in the markets by the 
name of manna in tear. 
The manna referred to by the ancient Greek writers is asserted, by Dr. Fothergill, to be portions of 
olibanum, broken off in the carriage of larger pieces, which by some is still called “ manna of frankincense.” 
The Arabians are supposed to be the first who brought manna into medicinal use. 
Qualities and Chemical Properties. — Pure manna is very light, and appears to consist of a 
congeries of fine capillary crystals. Its taste is sweet, and it leaves a nauseous impression on the tongue. 
When dissolved in water, it may be obtained again unaltered by a gentle evaporation. Alcohol dissolves it 
when assisted by heat; and the solution, when set aside, gradually deposits about f ths of the manna, in a 
state of a fine white light spongy crystalline mass, bearing some resemblance to camphor. This depost has 
an agreeable sweet taste, and instantly melts upon the tongue like snow in warm water. This may be con- 
sidered as pure manna. It differs from sugar in the nature of its crystals, and in its more rapid solubility. 
By evaporating the solution, and setting it aside repeatedly, about |-ths more of the manna is deposited, 
but not so fine in colour, or taste, as the first precipitate. By evaporation to dryness, the remaining fth is 
obtained in the state of a thick extract, which cannot be easily reduced to dryness. This may be con- 
sidered as consisting chiefly of foreign bodies, to which manna owes its nauseous taste. Manna differs from 
common sugar in several remarkable particulars. It dissolves very readily and abundantly in alcohol, and 
crystallizes on cooling. When digested in nitric acid it yields both oxalic and saclactic acids ; whereas 
sugar only yields oxalic acid. It does not ferment like sugar, and of course does not seem capable of fur- 
nishing alcohol. 
The common manna of the shops, according to the experiments of Fourcroy and Vauquelin, consists 
of four different ingredients ; 1. Pure manna, which constitutes at least fths of the whole. 2. A little 
common sugar, which makes it fermentable to a small extent. 3. A yellow matter, with a nauseous odour, 
to which the purgative quality of manna seems owing. 4. A little mucilage convertible into saclactic acid. 
This last ingredient, however, seems to be hypothetical. 
Several substances seem to be convertible into manna. The juice of the common onion yields it, and 
it has been discovered in the juice of the melon, but not till it has fermented. 
Manna appears also to be formed and deposited by insects. 
Medical Properties and Uses.' — The medicinal properties of manna are those of a mild cathartic, 
for which purpose it was formerly much used in practice. As, however, from one to two ounces of this 
medicine scarcely produce any effect on adults, it is now seldom employed alone; but combined with 
senna, neutral salts, and other aperients, is often used to cover their taste. It is an innocent remedy in the 
hands of mothers, who frequently give it to their children in doses from one drachm to half an ounce dis- 
solved in water ; but, though mild in its operation, it is apt to produce flatulence and griping. 
Off. Prep. — Confectio sennae. L. E. D. 
Syrupus sennae. D. 
