Heterotopic (muscle) bioassay in ferrets: (A): The biceps femoris of a ferret is shown. A sample of CS-Platelet and a sample of CS were implanted in the muscle tissue. (B): Four weeks after implantation the x-ray evaluations showed the presence of radio-opaque formations only in correlation with the implantations of CS-Platelet. (C, E-H): At the histological evaluation, the radio-opaque formation appeared as an ossicle formed by trabecular bone. (D, I-L): No bone formation was observed in correspondence with the implantations of Calcium Sulfate alone. Hematoxylin and Eosin staining.