174 GLUCOSIDES OTHER THAN TANNINS. 



with which it splits up into sugar and melanthigenin when boil( 

 with a dilute acid. 



The so-called smilacin was also formerly regarded as allied 

 saponin, but the researches of Fliickiger 1 have shown that und( 

 this designation a mixture of substances has been described, tl 

 principal constituent of which was named parillin. This bod] 

 stands in close relation to sapogenin, the decomposition-prodw 

 of saponin ; and as the latter is contained in sarsaparilla, 2 it is 

 probable that parillin is produced from it during the life of the 

 plant. According to Fliickiger, parillin is not soluble in cold water 

 to any appreciable extent, but dissolves in 20 parts of boiling. It 

 is taken up by spirit of sp. gr. 0'S3 more easily than by stronger 

 or weaker alcohol. 3 Its reaction with cone, sulphuric acid re- 

 sembles that of saponin. Boiled with 10 per cent, sulphuric acid 

 it decomposes into sugar and parigenin, with production of a 

 green fluorescence. A similar fluorescence is also observed when 

 hydrochloric acid gas acts upon a solution in a mixture of chloro- 

 form and alcohol. 



Sapogenin resembles parillin in most of its properties. Eoch- 

 leder is of opinion that it still retains a little sugar, and is there- 

 fore really the result of an incomplete decomposition of saponin. 

 The violet colouration gradually produced when sapogenin is 

 dissolved in cone, sulphuric acid serves to distinguish the body 

 from digitoresin, which, according to Schmiedeberg, yields a yellow 

 solution. (See 155.) 



Indican may also be mentioned here, as, although it is not a 

 substance that can be unconditionally ranked as a glucoside, it 

 may nevertheless be compared with them as regards its constitu- 

 tion. By the decomposition of indican indigo-blue is produced, 

 together with a kind of sugar called indiglucin. I leave it, how- 

 ever, an open question whether the formation of indigo-blue is 

 preceded by that of indigo-white, which, it is true, readily yields 

 that substance by absorption of oxygen. Indican appears to 

 occur in many plants (leaves, etc.), but to undergo a partial 

 decomposition when they are slowly dried, and the black or blue 



1 Compare Fliickiger and Hanbury, ' Pharmacographia,' 646. 



2 Otten, ' Histiol. Unters. der Sarsaparillen,' Diss. Dorpat, 1876. Otten 

 estimated the saponin by the methods given in 78. 



3 Archivd. Pharm. [3], x. 535, 1877 (Pharm. Journ. and Trans. [3], viii. 



488). 



