This article addresses the issue of the shifting configuration of the normal and the pathological in 17th century medicine from the standpoint of the practice of human dissection. For centuries, boundaries separated anatomy and pathology with respect to the dead body. The former was the universal scientia of the perfect natural body, while the latter dealt with individuals and particulars but as living patients; only occasionally it referred to post-mortems as a minor form of evidence. In the 17th century, tremendous if slow changes affected the practice of dissection. Post-mortems became routine in many hospitals in Europe and began to serve theoretical and practical studies alike. Galilean and Cartesian philosophies were especially influential in reassessing the theoretical foundations of dissection. On the one hand, the importance accorded to all mechanical functions enhanced interest in morbid conditions for understanding normal animal economy, and on the other hand, it shaped perceptions of disease. The theory according to which brain membranes played a major role in the healthy and diseased body was representative of this shift, which exploited pathological observations for normal physiology. This was an outcome of the conditions in which anatomy and morbid anatomy were practiced, namely the widespread use of post-mortems in urban hospitals in Italy.