The first textbook of dermatopathology. "Simon dated the preface of his book April 1st, 1848 and wrote (p. vi and vii) that much has been achieved by meticulous clinical description of diseases of the skin but now attention has to be given to the „Bestandtheile des so zusammengesetzten Hautorgans bei den einzelnen Krankheiten", that is, attention to the „parts of which the skin is composed in different diseases", with the aid of anatomo-pathological investigations. His treatise comprises of 400-odd pages and on some matters gives admirably detailed descriptions and sketches. His most important discovery, which made him an immortal of dermatopathology, was the discovery of the demodex folliculorum, the acne mite, in 1842. The coverage of the different areas of dermatopathology was very unbalanced, John Crissey, our grand master of dermato-history has remarked on that. We should keep in mind, however, that sections were made by hand, i.e. with a knife and not by microtome, and there were no stains yet. Especially the epidermal hypertrophies and neoplasms, the blisters of the skin and the parasites were well covered" (http://www.biusante.parisdescartes.fr/sfhd/ecrits/euroderm.htm, accessed 7-2-2016).  Digital facsimile from the Hathi Trust at this link.