226 THE SOURCES OF MANNA. 



manna runs down the smooth bark more easily. The next year the unin- 

 jured side is cut. The Manna cannelata is obtained from the upper inci- 

 sions, more than forty of which may be counted on one tree. The sap there 

 is not so fat as below, and consequently dries more easily into tubes and flat 

 pieces. After the manna has been removed from the trees it has further to 

 be dried on shelves before being packed in cases. The masses left adhering 

 to the stems, after removing the inserted leaves, are scraped off, and consti- 

 tute the Manna cannelata in fragmentis. Cannelata, can. in fragm. and 

 Capace are collected at the same time from one stem — the more Cannelata 

 from the younger, and the more Capace or Gerace from the older part of 

 the stem. In Sicily the latter is designated in sortie, and is probably the 

 most active. Dry and warm weather is essentially requisite for a good 

 harvest. 



Manna is a gentle tonic, usually operating mildly, but in some cases pro- 

 duces flatulence and pain. Mannite is white, inodorous, crystalhsable, in 

 semi-transparent needles, of a sweetish taste, soluble in five parts of cold 

 water, scarcely soluble in cold alcohol, but readily dissolved by that liquid 

 when hot, and deposited when cool. Unlike sugar, it is incapable of pro- 

 ducing the vinous fermentation. Manna sugar, or Mannite, differs from 

 the other sugars in not being fermentescible. Its composition is C 6 H>0 6 , 

 while that of cane sugar is C 12 H 9 9 x 2HO. It is the chief ingredient of 

 manna. 



The imports of manna into the United Kingdom are very variable. In 

 1855 as much as 94,274 lbs. were imported, and in 1856, 30,917 lbs. In 

 the subsequent three years the imports were smaller. 



Imports. Computed 



lbs. value. 



1857 15,365 £3,329 



1858 26,752 6,303 



1859 23,271 5,110 



M. A. Leuchtweiss (Annalen der Chemie) has examined the three varieties 



most commonly met with in the market, and the following are the results 



of his analyses : — 



Manna rjannplata Manna 



Cannelata. £iu*Wa CalaMna . 



Water 11-6 130 11-1 



Insoluble substance 0*4 0'9 3 - 2 



Sugar 9-1 10'3 15-0 



Mannite 42-6 37"6 32-0 



Substances similar to vegetable 



mucus with mannite, resinous 



and acid substance, with a 



small quantity of nitrogenous 



matter 40'0 40*8 42-1 



Ashes 1-3 1-9 1*9 



Total 105-0 104-5 105'8 



