As we study the nervous systems of animals, we find that with the apparent growth of intelligence there is a development of that part of the brain called the cerebrum. In so far as certain other parts of the brain are concerned--medulla, pons, mid-brain, basal ganglia cerebellum--we who are human are not essentially superior to the dog, the cow, the elephant or the monkey. But when the neopallium, or the cerebrum, is considered, the enormous superiority of man (and the superiority of the higher over the lower animals) becomes striking. Anatomically the cerebrum is a complex elaboration of cells and fibers that have these main purposes: First, to record in perfect and detailed fashion the EXPERIENCES of the organism, so that here are memory centers for visual and auditory experiences, for skin, joint and bone experiences of all kinds, speech memories, action memories, and undoubtedly for the recording in some way not understood of the pleasure-pain feelings. Second, it has a hold, a grip on the motor mechanism of the body, on the muscles that produce action, so that the intelligence can nicely adapt movement to the circumstances, to purpose, and can inhibit the movements that arise reflexly. Thus in certain diseases, where the part of the brain involved in movement is injured, voluntary movement disappears but reflex action is increased. Third, the neopallium, or cerebrum, is characterized by what are known as association tracts, i.e., connections of intricate kinds which link together areas of the brain having different functions and thus allow for combinations of activity of all kinds. The brain thus acts to increase the memories of the past, and, as we all know, man is probably the only animal to whom the past is a controlling force, sometimes even an overpowering force. It acts to control the conduct of the individual, to delay or to inhibit it, and it acts to increase in an astonishing manner the number of reactions possible. One stimulus arousing cerebral excitement may set going mechanisms of the brain through associated tracts that will produce conduct of one kind or another for years to come.