This chapter describes the anatomical period, in which postmortem dissections were rare, and in which views as to the nature of phthisis were based almost solely on the symptoms recognised during life. Hippocrates, Galen, Aretaeus, and Celsus all described the disease, but not one of them appears to have recognised the existence of the tuberculous nodules which form its characteristic lesion. Matthew Baillie recognised that the large nodules in tuberculosis are produced by fusion of smaller tubercles. The adoption of experimental methods of investigation of tuberculosis led to further advance towards precision of knowledge. Rokitansky, whose book on Pathological Anatomy first appeared in 1842, declared that tubercles were new growths composed of inspissated proteins. Villemin had made the statement that tuberculosis could be spread by inhalation of the virus, and pointed out the role of dried expectoration in its dissemination. Tappeiner was the first to demonstrate on dogs the possibility of dissemination of infection in this way.