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no place for going over the evidence in detail, so I will simply indicate the conclusions which are most probable at the date of writing.

Mental and Cerebral Elements.-In the first place, there is a very neat parallelism between the analysis of brainfunctions by the physiologists and that of mental functions by the analytic' psychologists.

The phrenological brain-doctrine divided the brain intc 'organs,' each of which stood for the man in a certain partial attitude. The organ of Philoprogenitiveness,' with its concomitant consciousness, is an entire man so far as he loves children, that of Reverence' is an entire man worshipping, etc. The spiritualistic psychology, in turn, divided the Mind into 'faculties,' which were also entire mental men in certain limited attitudes. But 'faculties' are not mental elements any more than 'organs' are brainelements. Analysis breaks both into more elementary constituents.

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Brain and mind alike consist of simple elements, sensory and motor. "All nervous centres," says Dr. Hughlings Jackson, "from the lowest to the very highest (the substrata of consciousness), are made up of nothing else than nervous arrangements, representing impressions and movements. I do not see of what other materials the brain can be made." Meynert represents the matter simi larly when he calls the cortex of the hemispheres the surface of projection for every muscle and every sensitive point of the body. The muscles and the sensitive points are represented each by a cortical point, and the Brain is little more than the sum of all these cortical points, to which, on the mental side, as many sensations and ideas correspond. The sensations and ideas of sensation and oi motion are, in turn, the elements out of which the Mind is built according to the analytic school of psychology. The relations between objects are explained by 'associations' between the ideas; and the emotional and instinctive tendencies, by associations between ideas and movements

The same diagram can symbolize both the inner and the outer world; dots or circles standing indifferently for cells or ideas, and lines joining them, for fibres or associations. The associationist doctrine of ideas' may be doubted to be a literal expression of the truth, but it probably will always retain a didactic usefulness. At all events, it is interesting to see how well physiological analysis plays into its hands. To proceed to details.

The Motor Region.-The one thing which is perfectly well established is this, that the central' con

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FIG. 41.-Left hemisphere of monkey's brain. Outer surface.

volutions, on either side of the fissure of Rolando, and (at least in the monkey) the calloso-marginal convolution. (which is continuous with them on the mesial surface where one hemisphere is applied against the other), form the region by which all the motor incitations which leave the cortex pass out, on their way to those executive centres in the region of the pons, medulla. and spinal cord from

which the muscular contractions are discharged in the last resort. The existence of this so-called 'motor zone' is established by anatomical as well as vivisectional and pathological evidence.

The accompanying figures (Figs. 41 and 42), from Schaefer and Horsley, show the topographical arrangement of the monkey's motor zone more clearly than any description.

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FIG. 42.-Left hemisphere of monkey's brain. Mesial surface.

Fig. 43, after Starr, shows how the fibres run downwards. All sensory currents entering the hemispheres run out from the Rolandic region, which may thus be regarded as a sort of funnel of escape, which narrows still more as it plunges beneath the surface, traversing the inner capsule, pons, and parts below. The dark ellipses on the left half of the diagram stand for hemorrhages or tumors, and the reader can easily trace, by following the course of the fibres, what the effect of them in interrupting motor currents may be.

One of the most instructive proofs of motor localization in the cortex is that furnished by the disease now called aphemia, or motor aphasia. Motor aphasia is neither loss. of voice nor paralysis of the tongue or lips. The patient's voice is as strong as ever, and all the innervations of his

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FIG. 43. Schematic transverse section of the human brain, through the rolandic region. S, fissure of Sylvius; N.C., nucleus candatus, and N.L., nucleus lenticularis, of the corpus striatum: O.T., thalamus; C, crus; M. medulla oblongata; VII, the facial nerves passing out from their rucleus in the region of the pons. The fibres passing between O.T. and N.L. constitute the socalled internal capsule.

hypoglossal and facial nerves, except those necessary for speaking, may go on perfectly well. He can laugh and cry, and even sing; but he either is unable to utter any words at all; or a few meaningless stock phrases form his only speech; or else he speaks incoherently and confusedly,

mispronouncing, misplacing, and misusing his words in various degrees. Sometimes his speech is a mere broth of unintelligible syllables. In cases of pure motor aphasia the patient recognizes his mistakes and suffers acutely from them. Now whenever a patient dies in such a conlition as this, and an examination of his brain is per

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FIG. 44.-Schematic profile of left hemisphere, with the parts shaded whose destruction causes motor ('Broca') and sensory (Wernicke') aphasia.

mitted, it is found that the lowest frontal gyrus (see Fig. 44) is the seat of injury. Broca first noticed this fact in 1861, and since then the gyrus has gone by the name of Broca's convolution. The injury in right-handed people is found on the left hemisphere, and in left-handed people on the right hemisphere. Most people, in fact, are left-brained, that is, all their delicate and specialized movements are handed over to the charge of the left hemisphere. The ordinary right-handedness for such movements is only a consequence of that fact, a consequence which shows out

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