PRESENCE OF A TRUE MANNA ON A BLUE GRASS. 297 
CHEMICAL INVESTIGATION. 
Preliminary Examination.—The manna when dissolved in 
water has a sweet taste. It has slight reducing properties, giving 
a distinct reaction when heated with Fehling’s solution, thus 
showing the presence of a reducing sugar. When a portion was 
boiled in dilute acid, the amount of copper reduced was apparently 
but little increased, indicating that other sugars were present, 
but in small quantity. It was thus seen that the sweetness of 
the manna must be derived from some other substance than sugar, 
and further tests discovered a crystallised body, of sweet taste, 
present in large quantities, and as seen below this substance is 
mannite, Besides the mannite and sugars, the manna contains 
a small quantity of gum, but no resin. Starch is also absent. . 
An aqueous solution is acid to test ‘paper. The identity of this 
acid was not determined, as the material at our disposal was not 
sufficient for that purpose, being used in other portions of the 
Inquiry. 
Moisture and Ash.—The amount of moisture in the powdered 
mania was found to be 7:19 per cent. It was heated in the air- 
bath at about 100° ©. until constant. This dried material was 
then incinerated, and the ash found to equal 2°39 per cent., a 
portion of which was dirt. The inorganic constituents present 
were chlorine, sulphuric, phosphoric, and a trace of nitric acids, 
also carbonic acid from the decomposition of the organic matter. 
The bases being alumina, iron, lime, magnesia and the alkalis. As 
the material at our disposal was required for the organic work, a 
thorough quantitative analysis of the constituents of the ash was 
not made, but it appears to be derived from the grass debris, and 
the substances insoluble in water, together with some foreign 
admixture, 
Estimation of the Glucose and other Sugars.—Two grams of the 
manna were dissolved in water and made up to 200 cc. It was _ 
found that it required 117 cc. of the solution to reduce 5 cc. of 
Fehling’s copper solution, 5cc. = 025 gram glucose, The manna 
therefore contains 2:15 per cent. of a glucose. 
