A patient, who had undergone removal of a meningioma and the involved dura, developed Jacksonian fits in the postoperative period. There had been precocious resorption of the patch of lyophilized dura mater used to repair the dural defect and this was followed by development of a pseudomembrane adherent to the cortex. After its removal, the patient recovered completely. Activation of reactive reparative processes, proliferative action by fibroblasts, reabsorptive phenomena, new vessel formation, are the main pathological events involved in this as in similar cases, but their sequence and the precipitating cause are not easily recognizable.