A novel system and method for treating ischemic neurologic tissue is disclosed wherein an oxygenated nutrient emulsion is circulated through at least a portion of the cerebospinal pathway. The nutrient emulsion contains an oxygenatable non-aqueous component, an aqueous nutrient component, an emulsification component, and other components which render physiologic acceptability of the nutrient emulsion. Methods for producing the nutrient emulsion and a system for delivering that emulsion to the crebrospinal pathway are also disclosed. Additionally, novel diagnostic methods for diagnosing the physiologic state of hypoxic-ischemic and other diseased neurologic tissue during treatment are provided.