As regards the recovery of motor power after lesions of the motor cortex, two processes seem at work which are termed respectively _restitution_ and _compensation_. By the former is understood the recovery obtained when a part of a "centre" is destroyed, and the rest of the centre, although thrown out of function at first, recovers and supplements the deficiency later. An example of restitution would be the recovery from temporary hemianopia caused by a small injury in one occipital lobe. By compensation is understood the improvement of an impaired nervous function, traceable to other centres different from those destroyed supplying means to compass the reaction originally dependent on the centres subsequently destroyed. Instances of such compensation are the recovery of taxis for equilibrium subsequent to destruction of the labyrinth of the ear, where the recovery is traceable to assistance obtained through the eye. It will be noted that these instances of recovery by restitution and by compensation respectively are taken, from cases of injury inflicted on receptive rather than on motor centres. It is doubtful how far they really apply to the undoubted improvement that does within certain limits progress and succeed in partially effacing the paresis immediately consequent on lesions of the motor area. It has to be remembered that in all cases of traumatic injury to the nervous system, especially where the trauma implicates the central nervous organ, the first effects and impairment of function resulting are due to a mixed cause, namely on the one hand the mechanical rupture of conducting paths actually broken by solution of their continuity, and on the other hand the temporary interruption of conducting paths by "shock." Shock effects are not permanent: they pass off. They are supposed to be due to a change at the synapses connecting neurone with neurone in the grey matter. They amount in effect to a long-lasting and gradually subsiding inhibition.
For diseases of the brain see NEUROPATHOLOGY, INSANITY, SKULL (_Surgery_), &c. (C. S. S.)
[1] The literature of the pineal region is enormous. Studnicka (in _Oppels Vergleichende mikrosk. Anat._ Teile 4-5, 1904, 1905) gives 285 references. The present conception of the generalized arrangement is: ([alpha]) A single glandular median organ from the fore-brain called the paraphysis. ([beta]) A pouch of the ependymal roof of the ventricle called the dorsal sac. ([gamma]) A right and left epiphysis, one of which may be wholly or partially suppressed. These may change their position to anterior and posterior in some animals.