536 



III. " Results of the Examination of certain Vegetable Products 

 from India." Parti. By JOHN STENHOUSE, LL.D._,F.R.S. 

 Received November 14, 1855. 



(Abstract.) 



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 cannabina. 



The first of these substances which I examined consisted of a 

 quantity of the roots of the Datisca cannabina, from Lahore, where 

 this plant is employed to dye silk of a fast yellow colour. The 

 roots, which had been cut into pieces about 6 or 8 inches long, were 

 from a half to three-quarters of an inch in thickness. They had a 

 deep yellow colour. A decoction of the leaves of the Datisca canna- 

 bina 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 accu- 

 rate 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 datiscine used as syno- 

 nymous with inuline. Thus in Braude's ' Chemistry,' vol. ii. 

 p. 1168, we find it stated that a variety of names had been given to 

 inuline, such as " dahline, datiscine," &c. 



The bruised roots were extracted in a Mohr's apparatus by long- 

 continued digestion with wood-spirit. The liquor obtained, which 

 had a dark brown colour, was Concentrated by distilling off a por- 

 tion 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, 1816, iii. 277. 



