Delayed union and nonunion in fractures of the long bones has for years been a fertile field for investigation and the source of much thought by surgeons specializing in conditions of the bones and joints. Many theories as to the cause of the aforementioned conditions have been advanced. Chief among them should be mentioned: (1) insufficient immobilization by improper splinting; (2) infection, either primary due to compounding of the fracture, or secondary, due to lack of aseptic technic at open reduction; (3) previous or concurrent organic disease, such as syphilis, tuberculosis, etc.; (4) general asthenia with low metabolic rate and diminution in the cellular and hemoglobin content of the blood; (5) the lowered calcium phosphorus content of the blood as determined by laboratory methods; (6) interposition of tissue, such as muscle, fascia, fat, etc.; (7) the type of suture material selected for internal fixation, such as various forms of catgut,