The Existence of the Freudian Unconscious in the Structure and Function of the Nervous System*

I shall endeavour to identify the nervous localisation of the Freudian unconscious, the anatomical substratum of unconscious elaborations.

The adaptation of the organism to the exigencies of life has demanded an unceasing struggle, a permanent co-operation between the instinct and the cerebral cortex.

The absolute reflex does not enable the organism to feed itself except if one introduces the food directly into the animal's mouth. Under the influence of the cerebral cortex, animals begin to recognize their food from a distance, they recognize the man who usually brings them their food and the place where they are fed. Thus, each factor of the exterior reality associated for a while with the innate reflex becomes a signaller of the preservation instinct, which evokes to the organism either the expectation of food, that of a sexual requirement or that of the defence instinct. In co-operation with the cerebral cortex, the preservation instinct acquires new, multiple and complex reactions, which take the place of the innate and invariable reactions of the absolute reflex. Pavlov has given to these reflexes the name of conditioned reflexes as they are produced by the co-operation of the cortex; they appear, disappear and appear again automatically, commanded by the organism's requirements.

Inferior animals respond to the limited excitations of the surrounding medium by typical, automatized reaction of their rudimentary nervous system. When the exigencies of the surrounding medium go beyond a certain limit, animals acquire new, varied and labile reactions, owing to the elaboration of conditioned reflexes.

The human nervous system has developed on biogenetic bases corresponding to the social exigencies of the fundamental ages which mankind has passed through. There was a cave age during which the individual responded to the excitations of life according to the instinctive reactions of his ancestral brain. Intergrated into human physiology, the animal requirements correspond to