_The Speech Zone._--Many interesting facts of the relation of body and mind have come to light in connection with the speech functions. Speech is complex, both on the psychological and also on the physiological side, and easily deranged in ways that take on such remarkable variety that they are a source of very fruitful indications to the inquirer. It is now proved that speech is not a faculty, a single definite capacity which a man either has or has not. It is rather a complex thing resulting from the combined action of many brain centres, and, on the mental side, of many so-called faculties, or functions. In order to speak a man normally requires what is called a "zone" in his brain, occupying a large portion of the outside lateral region (see Fig. 5). It extends, as in the figure, from the Rolandic region (_K_), where the kinaesthetic lip-and-tongue memories of words are aroused, backward into the temporal region (_A_), where the auditory memories of words spring up; then upward to the angular gyrus in the rear or occipital region (_V_), where in turn the visual pictures of the written or printed words rise to perform their part in the performance; and with all this combination there is associated the centre for the movements of the hand and arm employed in writing, an area higher up in the Rolandic region (above _K_). In the same general zone we also find the music function located, the musical sounds being received in the auditory centre very near the area for words heard (_A_) while the centre for musical expression is also in the Rolandic region. Furthermore, as may be surmised, the reading of musical notation requires the visual centre, just as does the reading of words. In addition to this, we find the curious fact that the location of the whole speech zone is in one hemisphere only. Its location on the left or the right, in particular cases, is also an indication as to whether the person is right-or left-handed; this means that the process which makes the individual either right or left-handed is probably located in the speech zone, or near it. A large majority of persons have the speech zone in the left hemisphere, and are right-handed; it will be seen that the figure (5) shows the left hemisphere of the brain, and with it the right hand holding the pen. _Defects of Speech--Aphasia._--The sorts of injury which may befall a large zone of the brain are so many that well-nigh endless forms of speech defect occur. All impairment of speech is called Aphasia, and it is called Motor Aphasia when the apparatus is damaged on the side of movement.