1. Transplants of articular cartilage with a thin adjoining osseous border were inserted anatomically in the knee and wrist joints of forty-two adult mongrel dogs and studied histologically at intervals ranging from five to 500 days.
2. Autogenous transplants of large articular fragments and half joints were often successful.
3. Homogenous transplants of large articular fragments and half joints, not at first, but eventually, showed degenerative changes and disintegration when subjected to weight-bearing function.
4. Within the degenerated homograft, articular cartilage foci persisted and remained viable for more than one year.
5. Both autogenous and homogenous transplants of cartilage into muscle showed gradual degenerative changes and absorption.