MICROCHEMIS TR Y. 8 



c. Asaron, C 6 H a .(OCH 3 ) 8 .C s H B . 



133. Asaron occurs especially in the rhizome and the 

 root of Asarum europceum and is here dissolved in what is 

 very probably an ethereal oil, which almost entirely*fills many 

 parenchymatous cells of the bark. It is distilled over with 

 water vapor and forms colorless crystals which are insoluble 

 in water, but readily soluble in alcohol, ether, chloroform^ 

 and acetic acid. 



For its microchemical recognition Borscow (I, 18) recom- 

 mends especially concentrated sulphuric acid, which colors it 

 first yellow, and later orange. The oil-drops containing 

 asaron, which are found in fresh sections, give the same 

 reaction. 



2. Acids. 



a. Tyrosin, p-Oxyphenyl-a-amidopropionic Acid, 

 C 6 H 4 OH.CH 2 .CHNH 2 .COOH. 



134. Tyrosin has been microchemically recognized in vari- 

 ous parts of plants, especially by Borodin (II, 816 and III,, 

 591). He proceeded by treating sections of the objects to 

 be tested with alcohol and then allowing them to dry slowly. 

 Tyrosin then crystallizes out in dendritic or tufted groups 

 of strongly refractive needles. 



These are rather slightly soluble in water (in 2454 parts at 

 20 C., in 154 parts at 100 C., according to Beilstein, II y 

 1006) ; and they are of course insoluble in a concentrated 

 aqueous solution of tyrosin ; but Borodin's method ( ;i r 

 note) is difficult to use with precision in this case, on account 

 of the slight solubility of tyrosin. It is, however, character- 

 istic of tyrosin crystals that they are colored deep red by 

 Millons reagent. They also leave a yellow residue when 

 they are carefully evaporated with nitric acid. From this 

 arises a deep red-yellow fluid, on the addition of caustic 

 soda ; and, after it dries, a red-brown crystalline deposit 

 remains (Leitgeb II, 229). 



135. According to Leitgeb (II) the crystallization of tyro- 

 sin is more or less completely prevented by the presence of 



