They [books] do preserve as in a vial the purest efficacy and extraction of that living intellect that bred them.
Milton.
The extraction of roots. (Math.) (a) The operation of finding the root of a given number or quantity. (b) The method or rule by which the operation is performed; evolution.
Ex*tract"ive (?), a. [Cf. F. extractif.] 1. Capable of being extracted. "Thirty grains of extractive matter." Kirwan.