A Synoptic Key of the Materia Medica

Cyrus Maxwell Boger, MD (1861–1935) was an American homeopath of the Boenninghausen school. Based in Parkersburg, West Virginia, he corresponded with the leading homeopaths of Europe and is considered one of the most rigorous analytical prescribers in the history of the profession.

Boger was a German speaker and translated much of Boenninghausen's work into English. His own contribution was to combine Boenninghausen's generalist approach — emphasizing modalities, concomitants, and sensations — with the American clinical tradition.

A Synoptic Key of the Materia Medica was first published in 1915 and revised through 1931. It is a one-volume reference that combines a materia medica, a repertory, and a summary of Boger's analytical method.

The materia medica section is organized around generals, modalities, and characteristic concomitants — in the Boenninghausen style — rather than the anatomical head-to-toe schema used by Boericke. This makes it ideal for cases where the modalities are clear but the particulars are diffuse.

Together with General Analysis, the Synoptic Key forms the core of Boger's practical teaching.