first published in 1892, this monograph remains an important reference for pharmacists, chemists, and anyone involved in the preparation of medicinal extracts. harrop provides detailed instructions on the various processes involved in extracting therapeutic compounds from plants and other sources, along with useful tables and formulas. the book also includes an appendix containing information on pharmaceutical calculations and other practical matters.this work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it.this work is in the "public domain in the united states of america, and possibly other nations. within the united states, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. we appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.