<h3>Plantar Callus and Diabetic Ulceration Treated by Injectable Liquid Silicone. Presented by Stanton B. May, MD, and S. W. Balkin, DPM (by invitation).</h3> A female diabetic patient, aged 58 years, had a callus under her left first metatarsal head for 20 years. In 1964, an ulcer developed at the site (Fig 1) and persisted until 1966 despite diabetic management and podiatric care twice monthly. Excessive weight coupled with a marked pes cavus eventually required complete avoidance of weight-bearing before the ulcer would heal. During April and May 1966, 4.9 ml of silicone (Dow Corning 360 Medical Silicone Fluid of 350 centistokes viscosity) was injected beneath the keratosis at the site of the healed diabetic ulcer. This woman worked full time for five years following injection, during which period palliative care for the callus was provided at six-week intervals, as opposed to monthly care prior to injections. In the past year,