1. Freeze-dried cortical grafts in dogs are definitely superior to similar frozen grafts in the rate of healing. This is especially true in the earlier stages of healing, but it is also rather marked in the later stages.
2. This advancement of freeze-dried bone-graft healing occurred in spite of a considerably longer average storage period for freeze-dried grafts than for frozen grafts.
3. The superiority of freeze-dried bone grafts over frozen grafts demonstrated in this series is much more striking than that in the original experimental comparison. This is probably the result of improvements in the technique of freeze-drying and storage of freeze-dried grafts in vacuum.