Beginning of modern concept of inflammation: the work of Friedrich Daniel von Recklinghausen and Julius Friedrich Cohnheim

Abstract In Rudolf Virchow’s concept of inflammation, the basic alterations were derived from connective tissue cells, which underwent a marked metamorphosis. This cell based and static conception was fundamentally broa dened and, in part, refuted in the ensuing decade by 2 of his scholars. Friedrich Daniel von Recklinghausen characterized the pus cells in acute inflammation and made the seminal observation of their contractility and mobility. He was the first who described the wande ring leukocytes which were demonstrated in particular in experimental keratitis. He also showed that pus cel ls could migrate from the places of their origin in the interstitium to other tissues and epithelial cells. Von Recklinghausen in addition contributed to the concept of phagocytosis. The work of Julius Friedrich Cohn heim was focused on the mechanisms involved in the extravasation of leukocytes from the blood vessels in the inflamed mesentery of the frog and carefully de scribed the time-dependent alterations: dilatation of the arteries and veins, adhesion of colorless cells to the endothelial cells, and the subsequent transmigra tion from the capillaries and venules into the interstitial space. In the last few decades, experimental and cli nical studies using modern techniques have fully con firmed and extended these basic observations made by von Recklinghausen and Cohnheim more than 100 years ago.