96 BOTANICAL MICROTECHNIQUE. 



it is decomposed with the formation of red masses, proba- 

 bly through the agency of a ferment. 



i. Rutin, C 42 H 50 O 2B . 



159. Rutin always occurs in the cell-contents, according^ 

 to O. Herrmann (I, 30). He recommends for its micro- 

 chemical recognition ammonia or lime-water, which form 

 deep-blue solutions with rutin, becoming brown on expos- 

 ure to the air. 



k. Saffron-yellow, Crocin, C 44 H 70 O 28 . 



160. The crocin contained in saffron is readily soluble in 

 water, less so in alcohol, and very slightly so in ether. It 

 dissolves in concentrated sulphuric acid with a blue color 

 which soon becomes violet and finally brown; in concen- 

 trated nitric acid with a deep blue color, quickly becoming 

 brown (Beilstein III, 357). According to Molisch (I, 57), 

 the last two reactions may well be used microchemically. 



/. Salicin, C 13 H 18 O 7 . 



l6oa. Salicin occurs especially in the bark of willows and 

 poplars. It is colored a beautiful red by concentrated sul~ 

 phuric acid (Rosoll I, 8). 



m. Saponin, C I9 H 30 O 10 . 



161. Saponin is dissolved in the cell-sap within the living 

 plant, according to Rosoll (I, 11), but is precipitated, on 

 drying, in the form of amorphous lumps within the cells ? 

 which may be readily observed in oil or glycerine. They 

 are dissolved in water or very dilute alcohol, but may be 

 precipitated from the solution by alcohol or ether. 



With concentrated sulphuric acid saponin gives at first a 

 yellow, then a bright red, and finally a blue-violet color. To 

 prevent confusion with Raspail's protein reaction (cf. 227), 

 which also differs in the colors produced, control sections 



