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VIII. Examination of select Vegetable Products from India. 
By John Stenhouse, LL.D., F.R.S. 
Received November 14, — Read December 6, 1855. 
PART I. 
Through the kindness of my esteemed friend Dr. Royle, I have been permitted 
to select such vegetable products from the extensive collection at the India House 
as seemed most likely to repay the trouble of investigation. My attention during 
the last twelve months has been chiefly directed to three of these vegetable sub- 
stances ; and the results of their examination I now take the liberty of submitting to 
the Royal Society, to be followed by those of the others as they may be completed. 
Datisca cannahina. 
The first of these substances which I examined consisted of a quantity of the roots 
of the Datisca cannahina, from Lahore, where this plant is employed to dye silk of a 
fast yellow colour. The roots, which had been cut into pieces about six or eight 
inches long, were from one-half to three-quarters of an inch in thickness. They had 
a deep yellow colour. The leaves and smaller branches of the Datisca cannahina from 
the Levant have long been employed for a similar purpose in the South of France. 
A decoction of the leaves of the Datisca cannahina was examined by Braconnot in 
1816, who discovered in it a crystallizable principle to which he gave the name of 
datiscine. Braconnot, of course, did not subject this substance to analysis, but he 
described its appearance and properties in an exceedingly accurate manner*. The 
observations of Braconnot had fallen into such entire oblivion, however, that for 
many years past, we find in most of the larger systems of chemistry the term datis- 
cine used as synonymous with inuline. Thus in Brande’s ‘ Chemistry,’ vol. ii. 
page 1168, we find it stated that a variety of names had been given to inuline, such 
as “dahline, datiscine,” &c. In Lowig’s ‘ Chemistry of Organic Compounds,’ vol. i. 
page 359, the same error is repeated, where, under the article ‘inuline,” the syn- 
onyms given are “dahline and datiscine.” 
The bruised roots were extracted in a Mohr’s apparatus by long-continued diges- 
tion with wood-spirit. The liquor obtained, which had a dark brown colour, was 
concentrated by distilling off a portion of the wood-spirit. The brown syrupy liquid 
remaining in the retort, on being poured into open vessels and standing for some 
* Annales de Chimie et de Physique (1830), iii. 277. 
MDCCCLVI. 
U 
