WIXTEEGREEX. 345 



It was also observed by Piccard, together with salicin and other 

 substances in the buds, bark, leaves and root bark of Populus 

 pyramidalis nigra and halsamifcra* Von Miiller describes 

 (Organic constituents of Plants) its preparation as follows: — "Boil 

 with water ; precipitate with subacetate of lead ; free the filtrate 

 from lead by sulphuric acid ; concentrate, boil w^ith animal 

 charcoal, and allow the salicin to crystallise. The mother liquor 

 yields with carbonate of potash a deposit of populin, which has to 

 be recrystallised from hot water." It crystallises in white, silky, 

 shining very voluminous needles. It much resembles salicin in 

 appearance, but, unlike that substance, its taste is penetratingly 

 sweet, the taste resembling that of liquorice. It loses the whole 

 of its water of crystallisation at 100^ C. It melts at 180"^ C, and 

 above that temperature it decomposes, yielding benzoic acid. It 

 dissolves in 2,420 parts of water at 15^ C, and in 42 parts at 

 100^ C.f Gerhardt says : " It dissolves in 2,000 parts of cold and 

 in 70 parts boiling water ; in 100 parts cold absolute alcohol : in 

 boiling alcohol more readily than in boiling water, and scarcely in 

 ether." It behaves towards concentrated sulphuric acid like 

 salicin, and forms, on boiling with dilute sulphuric acid, benzoic 

 acid, grape-sugar and saliretin. On heating with potassium 

 ■dichromate and sulphuric acid much salicylous acid is formed. 

 Boiling baryta decomposes it into salicin, and benzoic acid-emulsin 

 has no action upon it.:J: By heating it with alcoholic ammonia, 

 salicin, benzamide and ethyl benzoate are obtained. Nitric acid 

 oxidises it to henzoyl-hclecin, which is the corresponding aldehyde. 



The composition of populin was found § on the average of three 

 analyses to be 56-44 per cent, of Carbon, 6-27 per cent, of Hydrogen, 

 and 3 7*28 of Oxygen. 



Populin has been prepared artificially by Schiff,i! by fusincj 

 salicin with benzoic anhydride. 



An oil of pleasant balsamic odour is obtained by aqueous 

 distillation from the leaf-buds of Populus niger and other species 

 of Poplar. 



* Ber. Deutscli. Chem. Ges., vi., jj. 890. 



f Schmidt, Ann. Chem. Pharm., xix., p. 92. 



X Schmidt, ibid. 



§ Pharm. Joiirn., Feb., 1856. 



Jl Ann. Chem. Pharm., cliv., p. 5. 



