A major difficulty in the study of the chemical changes in a healing wound has been obtaining "wound tissue" relatively uncontaminated by normal tissues. Techniques have involved implanting or injecting different foreign bodies and then removing contiguous or ingrown tissue for analyses. The granulation tissue of surface wounds has been scraped off, and attempts have been made to excise only the wound from a healing rectus or other surgical incision in order to obtain the material for study. It appeared that the characteristic manner of tendon healing might provide a source to harvest less contaminated tissue.
A heel tendon of the dog, when cut and sutured, will heal with a small scar if the extremity is rigidly immobilized. However, should no immobilization be provided, the cut ends of the tendon will separate for 1 to 3 cm. and the interval filled by granulation tissue and then fibrous tissue. The tissue