they are components, or which must at least domesticate them, is stronger and more forcible if this serial stage is not unduly abridged. But, secondly, many, if not most, of these activities when developed a little, group after group, as they arise, must be controlled, checked, and organized into higher and often more serial compounds. The inhibiting functions are at first hard. In trying to sit still the child sets its teeth, holds the breath, clenches its fists and perhaps makes every muscle tense with a great effort that very soon exhausts. This repressive function is probably not worked from special nervous centers, nor can we speak with confidence of collisions with "sums of arrest" in a sense analogous to that of Herbart, or of stimuli that normally cause catabolic molecular processes in the cell, being mysteriously diverted to produce increased instability or anabolic lability in the sense of Wundt's _Mechanik der Nerven_. The concept now suggested by many facts is that inhibition is irradiation or long circuiting to higher and more complex brain areas, so that the energy, whether spontaneous or reflex, is diverted to be used elsewhere. These combinations are of a higher order, more remote from reflex action, and modified by some Jacksonian third level.[9] Action is now not from independent centers, but these are slowly associated, so that excitation may flow off from one point to any other and any reaction may result from any stimulus. The more unified the brain the less it suffers from localization, and the lower is the level to which any one function can exhaust the whole. The tendency of each group of cells to discharge or overflow into those of lower tension than themselves increases as correspondence in time and space widens. The more one of a number of activities gains in power to draw on all the brain, or the more readily the active parts are fed at cost of the resting parts, the less is rest to be found in change from one of these activities to another, and the less do concentration and specialization prove to be dangerous. Before, the aim was to wake all parts to function; now it is to connect them. Intensity of this cross-section activity now tends to unity, so that all parts of the brain energize together. In a brain with this switchboard function well organized, each reaction has grown independent of its own stimulus and may result from any stimulation, and each act, e.g., a finger movement of a peculiar nature, may tire the whole brain. This helps us to understand why brain-workers so often excel laborers not only in sudden dynamometric strength test, but in sustained and long-enduring effort. In a good brain or in a good machine, power may thus be developed over a large surface, and all of it applied to a small one, and hence the dangers of specialization are lessened in exact proportion as the elements of our ego are thus compacted together. It is in the variety and delicacy of