The state consciousness is associated with cortical activity activated by impulse from the thalamus and mid brain. The reticular formation receives collateral axons from the cortex and sends fibers to the cortex which it alerts. The lower part of the reticular formation projects to the spinal cord for regulation of muscles tone. Disorders of the cortical or brain stem poles of this system, but particularly the latter, are associated with disturbance of consciousness. Loss of consciousness is graded into arbitrary stages required to cause arousal. In the same way coma can be arbitrary graded according to the degree of loss of reflex activity. The ‘vital’ reflexes of coughing. Deepening coma and in treatment h patient must be protected form the consequences of their loss. Coma may be difficult to differentiate from some psychotic conditions of depression from amniotic autism in stimuli. If he is watched continuously it is seen that he is no wholly out of touch with his surrounding and his vital reflexes psychological abnormality can usually be obtained from a relative region of ht third ventricle but will be associated with signs of cerebral damage.