Carmichael "subdivided venereal infections into four major classes, each of which he maintained had a distinct exciting poison, a peculiar primary manifestation and a separate series of constitutional affections. From this he inferred that there were four varieties of morbid poison on which the existence of all these symptoms depended . . .Carmichael was correct in identifying that syphilis presented itself in many forms, both the primary and secondary lesions of syphilis can appear in one or in a variety of manifestations. His theory about the
plurality of poisons was however misdirected” (Spongberg, Feminizing Venereal Disease, p. 30). Digital facsimile from wellcomecollection.org at this link.

The 4 hand-colored plates of unusual and extreme cases are a feature of this work. In 1817 Nathaniel Chapman (1780-1853) paid for an American edition of Carmichael's work to be published in Philadelphia. That edition contained American copies of Carmichael's plates engraved by the American engraver Alexander Lawson (1773-1846). Those plates were among the finest engraved and hand-colored medical illustrations published in American up to that date. Lawson had previously been the engraver of the images in Wilson's American Ornithology, 9 vols., 1808-1814.