Experiments were undertaken to determine, if possible, answers to the above questions. A distinguished authority, Dr. John B. Murphy, has maintained that contact with living bone is absolutely and unconditionally necessary for the subsequent life of grafts. Thus, he expresses himself1as follows: In bone transplantations, there is but one absolute essential, other than rigid asepsis, and that is that the bone graft must be closely connected at some one point at least with living, freshened, osteogenetic tissue. Also2he says: Bone with or without its periosteum, transplanted into the muscle or cellular tissue, practically always dies and is absorbed, when it is free from bony contact. No proofs, however, were forthcoming to substantiate this conclusion, and it was with the object of helping to decide this question that the following experiments were performed. Figure 1 proves that strips and fragments of bone without periosteum, transplanted into the