DR. JOHN STENHOUSE ON VEGETABLE PRODUCTS FROM INDIA. 
143 
though it does not produce any change upon test paper, I think there is reason to 
regard it as a feebly acid body. It dissolves in solutions of the fixed alkalies and 
ammonia, as well as in lime and baryta water. Their solutions have a deep yellow 
colour, which they lose on the addition of an acid, when the datiscine is precipitated, 
even acetic acid precipitating datiscine. When its alkaline solutions are not too 
concentrated, and are neutralized while hot, the datiscine on cooling is deposited in 
small crystals. The aqueous solution of datiscine is precipitated by neutral and basic 
acetates of lead, or chloride of tin. These precipitates have a bright yellow colour. 
Salts of copper produce greenish precipitates ; those of peroxide of iron deep brown- 
ish-green precipitates. The datiscine employed in these experiments had been puri- 
fied with gelatine. 
The lead salts form such gelatinous precipitates, that they could not be washed, 
and therefore I was unable to employ them in determining the equivalents of 
datiscine. 
Action of dilute Sulphuric Acid on Datiscine. 
When an aqueous solution of datiscine is treated with a small quantity of sulphuric 
acid, the clear liquid, after being boiled for a few minutes, becomes turbid, and depo- 
sits a crystalline substance. This is collected on a filter, and the clear liquid which 
passes through, after it has been made strongly alkaline by the addition of potash, 
and after being heated to 212°, throws down suboxide of copper. When the excess 
of sulphuric acid is removed from another portion of the solution, by neutralizing 
with carbonate of lead or baryta, it acquires a sweet taste; and when evaporated to 
the consistence of a syrup, on standing for some time, it formed a semi-crystalline 
mass, closely resembling honey. This experiment showed therefore that datiscine, 
like salicine and similar bodies, belongs to the class of glucosides, and is a copulated 
compound of sugar and another substance which 1 shall call datiscetine. 
Datiscetine . — Datiscetine in its general appearance and properties closely resem- 
bles datiscine. On a closer examination, however, these two substances are found 
to differ essentially, both in composition and properties. Datiscine, when prepared 
by boiling a solution of pure datiscine with dilute sulphuric acid, precipitates in the 
state of fine needles, which are nearly colourless. It is easily soluble in alcohol; a 
hot alcoholic solution, on cooling, depositing the greater portion of it in crystalline 
groups. It is almost insoluble in water, and consequently datiscetine is abundantly 
precipitated from its alcoholic solutions by the addition of water. It dissolves in 
ether to almost any extent, and is deposited, on the evaporation of that liquid, in 
needles. 
These properties of datiscetine enable us to obtain it in a tolerably pure state when 
even very impure datiscine is employed in its preparation. The mother-liquors out 
of which datiscine has been crystallized, and which retain a large amount of impu- 
rities, can be used in the following way for the preparation of datiscetine. These 
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