The collection of 2837 items housed in the museum of Veretinary Pathology and Teratology "Alessandrini - Ercolani", established in 1863 as Museum of Comparative Pathology, has an educational and an historical interest, and comprieses: plastics in chalk, clay and wax, reproducting organic diseases in orignal volumes with theratological defects, a special exhibit of arthropathies, and lanrge number of colour drawings of pathological specimens mad by Cerate Bettini, the famous wax modeller of the same specimens.