Die Infusionsthierchen als vollkommene Organismen. 1 vol. and atlas of 64 hand-colored engraved plates.

In this monumental work in folio format Ehrenberg extended Otto Friedrich Müller’s bacteriological classification. Like Müller, he made no distinction between protozoa and bacteria, classing them both as infusoria. His classification included Bacterium, which he described and named in 1828, and published in 1830, Vibrio, Spirillum and Spirochaeta. The fine hand-colored plates in this book were drawn by Ehrenberg himself. Includes (p. 80) first description of B. subtilis.

Ehrenberg's book was translated into French with the atlas in reduced  8vo format and condensed to 8 uncolored plates, as Traité pratique du microscope, et de son emploi dans l'étude des corps organisés par le docteur L. Mandl; suivi de Recherches sur l'organisation des animaux infusoires par D.-C.-G. Ehrenberg. Accompagné de quatorze planches. (Paris: J.-B. Baillière, 1839). Digital facsimile of the 1839 translation from Biodiversity Heritage Library at this link.