Blood, monsters, and necessity in Malpighi's De Polypo Cordis.

The recent laudable translation of Malpighi's De polypo cordis has made widely available one of the most significant anatomical texts of the seventeenth century.' One of the treatise's most noteworthy features is the idea that the study of morbid states not only helps in the investigation of disease and therapy, but also in the understanding of the normal processes and constituents of the body, notably growth and blood. Malpighi's analysis of the formation of heart polyps led him to a tentative explanation of normal growth, one of the natural faculties of the Galenic tradition, on the basis of "the necessity of matter", without any teleological principle acting to the animal's benefit. In addition, the study of heart polyps provided Malpighi with the opportunity for investigating their constituents and therefore the constituents of blood. This essay details the circumstances of composition and publication date of Malpighi's work, shedding light on the peculiar publishing practices adopted. Secondly, I focus on the methodological significance of Malpighi's work, arguing that the difficulties he encountered in his research on the spleen and the heart polyp led him to develop a method of inquiry which I call the "microscope of disease". Lastly, I provide new translations and interpretations of some crucial passages in De polypo cordis. The first two deal with the polyp's formation process and its general significance in revealing how the body works, the other with the material forming the polyp and the constituents of blood.