For several years, Dr. William Keiller, with whom I have been associated in the Department of Anatomy of the University of Texas, has contended, from his study of the spinal cords of patients who have died as a result of fracture of the spine, that, since the spinal cord is encased within a fairly firm but apparently slightly elastic tube of pia mater, the cord pulp formed at the site of lesion in crushes resulting in ribbon-like injuries takes the path of least resistance and tracks up and down the cord pushing aside and destroying cord elements. It was with this theory in mind that we undertook a series of experiments on dogs and of studies on human cords obtained fresh at necropsy, the purpose being to study the mechanical factors involved in spinal cord crushes both complete and partial, and the subsequent vital changes occurring in such injuries. METHODS