138 ODOROGRAPHIA. 
point, it evolves pungent fumes of acetie acid, and ultimately 
leaves a thick oily body, an ethereal solution of which deposits 
crystals of coumarin on evaporation, which can be purified by 
crystallization from alcohol. It agrees in all its properties with 
the coumarin of the Tonka bean, C,H,O,. Its vapour has a 
powerful action on the brain*. 
The formation of coumarin by Perkin’s method, as above de- 
scribed, depends on the simultaneous formation of sodium-acetate, 
for when a mixture of acetyl-salicylol, acetic anhydride, and 
sodium acetate is heated to the boiling-point, a considerable 
quantity of coumarin is produced; acetylcoumarin being first 
formed, and then decomposed on heating into acetic acid and 
coumarin. 
Zwenger says{ that when sodium amalgam is added in small 
quantities to a solution of coumarin in water containing a little 
alcohol at 40°-60°, the coumarin is first converted by assumption of 
water into coumaric acid C,H,O,, and this, by further assimilation 
of nascent hydrogen, is transformed into melilotic (hydrocoumaric) 
acid, CysH,,03. 
Coumarin is also formed in small quantities when malic acid is 
heated with phenol and sulphuric acid f. 
Coumarie acid occurs, associated with coumarin, which is its 
anhydride, in common melilot and in Faham leaves§. It can be 
prepared by dissolving 3°5 grm. of sodium in 60—70 cb. em. of 
alcohol, adding 10 grm. of coumarin, and heating for one or two 
hours. Water is then added, the alcohol boiled off, and hydro- 
chloric acid added. ‘The precipitate is dissolved in a cold solution 
of sodium carbonate, the small quantity of coumarin which re- 
mains undissolved by ether, and the coumaric acid again preci- 
pitated with hydrochloric acid, and finally purified by recrystal- 
lization from hot water ||. It crystallizes in long needles which 
melt at 207°-208°, are slightly soluble in cold, more readily in 
boiling water, and readily in alcohol. It may be sublimed if 
carefully heated, but decomposes on distillation, with the forma- 
* Ber. Deutsch. chem. Ges. x. p. 284. 
+ Jahresh. 1865, p. 343, and 1867, p. 448. 
t Ber. Deutsch. chem. Ges. xvii. p. 929. 
§ Ann. Chem. Pharm. Suppl. viii. p. 30. 
|| Ber. Deutsch. chem. Ges. x. p. 284. 
