In the gradual evolution of resections of frontal, temporal and occipital lobes for the cure or attempted cure of invasive and otherwise incurable cerebral tumors, it has been found that the right temporal lobe, either frontal lobe or either occipital lobe (the left posterior to the supramarginal gyrus) could be completely removed without apparent mental impairment. It therefore seemed a logical expectation that the right cerebral hemisphere might be removed with little, if any, change in the mentality of a right handed person. At times patients already paralyzed on the left side from the inroads of cerebral neoplasms and without any prospect of its correction are eager to live, even at the price of permanent loss of function on that side of the body, if only the mind remains undisturbed. Five times during the past five years patients in this condition have urged every effort to save their lives, regardless