MICROCHEMISTR Y. 1 2 5 



the pepper-fruit are used. This turbidity is due chiefly to 

 the yellow resin which is also dissolved in the alcohol. 

 After a time (about a quarter of an hour) there are seen 

 -characteristic colorless crystals, especially abundant at the 

 edge of the cover-glass, which have very commonly an ap- 

 proximately sabre-shaped outline, but are not seldom grown 

 together in most various ways, 

 as is shown in Fig. 32, which rep- 

 resents crystals obtained by the 

 method described. All these 

 crystals give the piperine reac- 

 tions above described and un- ^%\ ^ 

 doubtedly consist of that sub- \P^ 



.stance. u 



Similar piperine crystals are 



formed, according tO Molisch FlG " 3 Crystals of piperine. 



{I, 28), within or in the vicinity of the piperine-cells of pep- 

 per, if thin sections are placed under a cover-glass in water 

 or glycerine and kept in a moist chamber for several hours. 

 * l Sections which are pressed and rubbed under a cover-glass 

 in water show piperine crystals within the first quarter of an 

 hour." 



k. Sinapine, C 16 H 32 NO a . 



218. This occurs in the seeds of white mustard as sinapine 

 sulphocyanide (C 16 H 32 NO a .HCNS). 



According to Molisch (I, 31), it is best recognized with a 

 concentrated solution of caustic potasJi. Sections of white 

 mustard seeds placed in this become at once yellow, and, on 

 warming, deep orange. But this reaction has a very limited 

 value, since the glucoside sinalbine, also found in white 

 mustard-seeds, becomes yellow with caustic potash. 



/. Strychnine, C 21 H 22 N 2 O 2 . 



219. Strychnine is dissolved without color by a concen- 

 trated sulphuric acid ; but if solid potassium bichromate be 

 added to the solution, a beautiful violet color appears at 



