It is our purpose in this paper to consider the healing strength of the fractured fibulae of rats on a standard diet. In a preliminary report on this subject, two of us (Dr. Lindsay and Dr. Howes)1 presented an original method for the determination of the healing strength of fibular calluses in rats from the inception of the fracture to the restitution of normal strength in the healing bone. The findings obtained at that time were in several instances later found to be either inadequate or inconclusive. However, on the basis afforded by this first contribution, the work has been carefully repeated with the result that a much better comprehension of the problem has been made possible. In some instances, important changes were made in technic, while in all cases the factors concerned have been clarified to a greater extent than existed before.
PROCEDURE
We found early that the