On Jan. 11, 1944, a 1-year-old, black Percheron mare was admitted to the Stange Memorial Clinic. The anamnesis volunteered by the owner was incomplete in that the etiology of the condition was unknown. Apparently, 3 days previously the horse had returned from the field with an injury located on the posterior medial side of the left thigh. At the time of entrance into the clinic, the wound was exuding a copious amount of purulent material, and a slight swinging leg lameness was being exhibited which was probably secondary in nature. Swelling and edema existed between the wound and the hock joint.