A tasteless white crystalline substance,
C9H6O3, found in the bark of a certain plant (
Daphne Mezereum), and also obtained by the distillation of certain gums from the
Umbelliferæ, as galbanum, asafetida, etc. It is analogous to coumarin. Called also
hydroxy-coumarin. Its strong fluorescence under ultraviolet light makes it useful in analytical biochemistry, as, for exmple, to detect phosphatase activity by hydrolysis of umbelliferyl phosphate. [
1913 Webster]