Since 1957, a body of evidence has been accumulating, slowly but steadily, indicating that cartilage from a variety of animal species and orders contains a substance (or substances) which accelerates the healing of wounds. Acid-pepsin digested cartilage, when properly milled, can produce increases of over 50% in the tensile strength of seven-day-old midline abdominal wounds in rats. The powder has been prepared from bovine adult and calf tracheal cartilage, from shark skeleton, from crocodiles, from teju lizards, and from human knee cartilage. All of these sources have proved to be active when properly prepared. The particle size and the age of the source animal appear to be important. Thus, when optimal size (about a 20μ average diameter) is combined with optimal age of the source (calf), a maximal increment in wound tensile strength of 52% is achieved.
Histological study of the phenomenon has also yielded interesting information. Cartilage-treated wounds exhibit