62 Royal Society: — 



datiscine, converting it into datiscetine and sugar. On boiling ail 

 aqueous solution of pure datiscine for some hours, traces of sugar 

 could be detected, thus showing that a small portion of the datiscine 

 had been decomposed. 



It has been already shown that datiscine dissolves in cold so- 

 lutions of potash without decomposition. When boiled, however, 

 with a strong solution of potash for some time, decomposition takes 

 place, and the precipitate, thrown down by the addition of an acid, 

 has all the properties of datiscetine. In this respect, therefore, 

 datiscine agrees with tannin and similar glucosides, which yield the 

 same products when acted upon by acids and alkalies. Yeast and 

 emulsine appeared to exert no action on solutions of datiscine. 



Action of Nitric Acid on Datiscine and Datiscetine. — Cold nitric 

 acid of the ordinary strength acts violently upon datiscetine, brown 

 vapours are disengaged, and a resinous substance is produced, 

 which is ultimately dissolved, forming a dark red liquid, which, 

 when evaporated, yields crystals of nitropicric acid. 



Datiscine treated in the same way yields nitropicric and oxalic 

 acids. 



When datiscine is boiled with dilute nitric acid it dissolves, and 

 the solution obtained, when cooled, deposits pale yellow crystals, 

 which agree in every way with the properties ascribed to nitrosali- 

 cylic acid. 



On allowing datiscine to stand in contact with dilute nitric acid 

 in the cold it gradually dissolves, the solution, when left to eva? 

 porate in vacuo, depositing a mixture of oxalic and nitropicric acids. 



Action of Potash on Datiscine and Datiscetine, — It was stated in a 

 previous part of this paper that datiscine and datiscetine dissolve in 

 cold solutions of the alkalies without decomposition, and that datis- 

 cine, when boiled with potash, is decomposed with the formation of 

 datiscetine. It only remained, therefore, to try the action of fused 

 hydrate of potash. Datiscetine, when added in small successive 

 portions to fused hydrate of potash, assumed a deep oiange colour, 

 and then dissolved with the evolution of hydrogen gas. When the 

 disengagement of hydrogen had ceased, the mass was dissolved in 

 water and supersaturated with hydrochloric acid. A partly resinous 

 substance separated, which, by sublimation, yielded perfectly colour- 

 less, long crystals closely resembling benzoic acid. Their solution 

 in water on the addition of perchloride of iron gave that deep violet 

 tint which disappears on the addition of hydrochloric acid, and is so 

 characteristic of salicylic acid. 



Action of Chromic Acid on Datiscetine. — On distilling datiscetine 

 with bichromate of potash and sulphuric acid a liquid came over, 

 containing no oily drops, but having the smell of salicylous acid, 

 and which, when tested with a persalt of iron, formed a purple- 

 coloured solution characteristic of that acid. 



It follows therefore, I think, from the experiments already de- 

 tailed, that datiscine, like salicine, phloridzine, &c., is a glucoside, 

 and that it approaches nearer to salicine than any other glucoside, 

 with the exception of populine, yet known. 



