ODOUR OF THE HAYFIELDS. 141 
This odour has been compared to Hawthorn. More complete 
details of the method of manufacture are given under that head. 
The odour of coumarin is observed on heating Umbelliferon, 
Daphnetin, and Methylumbelliferon. 
Umbelliferon, C,H,O;, is a neutral glucoside, obtamed by the 
dry distillation of various resins, chiefly of those derived from 
umbelliferous plants. Crude galbanum yields 0°83 per cent., 
sagepanum 0°32, and asafcetida 0°28 per cent. It is likewise 
obtained from the resins of Sumbul root and Angelica root. It is 
also obtainable from the alcoholic extract of the bark of Daphne 
Mezereum (the spurge-laurel), which also contains daphnetin. 
Umbelliferon may be easily prepared from galbanum by boiling 
the crude gum with water, dissolving the resinous residue in 
milk of lime, and precipitating the filtered solution with hydro- 
chloric acid. By distillmg this purified resin with water, an oily 
distillate is obtained which, on standing, deposits crystals of um- 
belliferon, to be purified by recrystallization. Umbelliferon is 
also formed when a concentrated alcoholic solution of pure gal- 
banum resin saturated with hydrochloric-acid gas is heated for 
some time to 100°. Umbelliferon may be synthetically prepared 
by heating resorcinol and malic acid with sulphuric acid, the 
reaction corresponding to the formation of coumarin from malic 
acid and phenol. 
Umbelliferon forms colourless rhombic prisms having a faint 
silky lustre; it is tasteless, odorous when cold, dissolves very 
slightly im cold water, and very abundantly in boiling water. It 
also dissolves in alcohol and chloroform. The aqueous solution 
is colourless by transmitted light, but exhibits by reflected light a 
splendid blue fluorescence. When umbelliferon is warmed it 
emits an odour like coumarin. Its aqueous solution when boiled 
emits the same odour. It melts at 224°, sublimes below its 
melting-point, and volatilizes without residue. It dissolves in 
concentrated sulphuric acid without decomposition, the solution 
showing a dark blue fluorescence. 
Water and sodium amalgam convert it into hydro-umbceliic acid. 
By boiling with dilute acids or by the action of emulsion it is 
converted into glucose and daphnetin, CgH,O,*. 
Daphnetin has been obtained synthetically by heating pyro- 
* Ann. Chem. Pharm. cvi. p. 1. 
