1. The long bones of the lower extremity are the biggest and strongest bones in the body. The force required to break them must necessarily be great, and the damage taking place at the time of injury is not only in the bone, but in the surrounding tissues. The speed of healing of fractures is usually proportionate to the amount of available circulation to and between the fragments.

2. In spite of the foregoing deduction, all the causes of delayed union and of non-union have not yet been determined.

3. The percentage of delayed union and non-union in fractures of the femur is not so great as in fractures of the tibia.

4. There are more cases of delayed union and non-union in the middle third of the tibia than in the upper and lower thirds.

5. The majority of our patients received some form of calcium therapy during their fracture treatment, with little recognizable effect on the end result.

6. In the instructions to patients and students, due consideration should be given to the slowness and uncertainty of the healing of fractures of the tibia and femur, so that patients may be prepared for the long period of time possibly necessary for the healing of these fractures.

7. The use of skeletal traction and the use of internal or external skeletal fixation in no way speeds the healing time of bone, and in some instances retards it, because of distraction, infection, or the osteolytic effect of the metals used.

8. In the series of cases here presented, circumstances in some instances necessitated the use of skeletal traction, plating, and external fixation (Haynes). In none did we feel that the results obtained by such methods were in any way superior to those of conservative treatment, when alignment could be maintained even at the expense of a loss of length of as much as three-quarters of an inch.