I. The development of the objective method in investigating the physiological activities of the cerebral hemispheres. -- Concept of Reflex. -- Variety of Reflexes. -- Signal-reflexes, the most fundamental physiological characteristic of the hemispheres -- II. Technical methods employed in the objective investigation of the functions of the cerebral hemispheres. -- Response to signals as reflex action. -- Unconditioned and conditioned reflexes. -- Necessary conditions for the development of conditioned reflexes -- III. The formation of conditioned reflexes by means of conditioned and direct stimuli. -- Agencies which can be used as conditioned stimuli. -- Inhibition of conditioned reflexes: external inhibition -- IV. Internal inhibition of conditioned reflexes: (a) Extinction -- V. Internal inhibition (continued): (b) Conditioned inhibition -- VI. Internal inhibition (continued): (c) Delay -- VII. The analysing and synthesizing activity of the cerebral hemispheres: (a) The initial generalization of conditioned stimuli. (b) Differential inhibition -- VIII. The analysing and synthesizing activity of the cerebral hemispheres (continued): (c) Examples of the analysis of stimuli. (d) Synthesis and analysis of compound simultaneous stimuli. (e) Synthesis and analysis of compound successive stimuli -- IX. The irradiation and concentration of nervous processes in the cerebral cortex: (a) The irradiation and concentration of inhibition within a single analyser -- X. Irradiation and concentration of nervous processes in the cerebral hemispheres (continued): (b) Irradiation and concentration of inhibition over the entire cortex; (c) Irradiation and concentration of excitation -- XI. Mutual induction of excitation and inhibition: (a) Positive induction. (b) Negative induction -- XII. Interaction of irradiation and concentration with induction -- XIII. The cortex as a mosaic of functions: (a) Examples of the mosaic character of the cortex and the more obvious ways in which this character is acquired; (b) Variability of the physiological properties of different points of the cortex in some instances, stability in others. -- The cortex as a united complex dynamic system -- XIV. The development of inhibition in the cortex under the influence of conditioned stimuli -- XV. Internal inhibition and sleep as one and the same process with regard to their intimate mechanism -- XVI. Transition stages between the alert state and complete sleep: hypnotic stages -- XVII. The different types of nervous system. -- Pathological disturbances of the cortex, result of functional interference -- XVIII. Pathological disturbances of the cortex, result of functional interference (continued) -- XIX. Pathological disturbances of the cortex, result of surgical interference: (a) General disturbances of the cortical activity; (b) Disturbances of the acoustic analyser -- XX. Pathological disturbances of the cortex, result of surgical interference (continued): (c) In the visual analyser; (d) In the tactile cutaneous analyser; (e) Occurring after extirpation of the frontal lobes; (f) In the thermal cutaneous analyser; (g) Arising after extirpation of the gyrus pyriformis; (h) In the motor analyser -- XXI. Pathological disturbances of the cortex, result of surgical interference (continued): Attempt to correlate the general postoperative behaviour of the animals with the disturbances in the activity of individual analysers -- XXII. The general characteristics of the present investigation and its special difficulties. -- Discovery of certain errors necessitating the modification of some earlier interpretations -- XXIII. The experimental results obtained with animals in their application to man.