Researches by Allison and Brooks1on the etiology of bone atrophy have led them to conclude that its character is the same regardless of the process, whether from poliomyelitis, traumatic nerve injuries, tuberculosis of bone, fracture, acute pyogenic osteomyelitis, simple fixation in plaster, or acquired and congenital deformities. In all of these conditions, lack of use is emphasized as the one causative factor in the production of bone atrophy. The same changes were observed regardless of the cause of disuse, and the amount of atrophy was directly proportional to the lack of use. The failure in growth in length of a bone in infantile paralysis is not due to any specific nerve influence destroyed by the disease, but the disuse alone results in a disturbance in growth as well as a thinning of the bone cortex and widening of the medullary canal. That there may be another factor having