Printed illustration in color of two opium masses. Opium is made from the juice from the capsules of Papaver somniferum which is then hardened by evaporation. The top, no. 16, is of a Smyrna Opium which is wrapped in poppy leaves and covered then by capsules of a species of Rumex. The lower, no. 17, is of a Constantinople Opium which is wrapped in a poppy leaf.

This manual identifies plants used for medicinal purposes. The focus is on plants that can be acquired through commerce in Britain and are illustrated as they would have been imported and bought, for example the opium is illustrated as a processed capsule wrapped in a poppy leaf instead of the poppy plant itself.

Authored by George Sampson Valentine Wills (1849-1932). Wills was the founder and Director of the Westminster College of Chemistry and Pharmacy in London. The school was established to train druggists for examinations by the Pharmaceutical Society of Great Britain, the regulating body established in 1841.