These courts of inquiry are called association centres. It used to be believed that they were all in the fore-part of the brain, under the forehead; but this is evidently not the case. Several men in war or by accident have had the frontal lobes of their brain damaged beyond repair; and when they have been discharged from hospital, where, thanks to the advance made by surgery since anæsthetics and antiseptics were discovered, they have been successfully treated, they have gone back to their work seemingly in no way different from men whose brains were whole. In some cases they have even been reported as having become quicker and sharper than before, probably owing to there being fewer association centres, and thought being accelerated by simpler machinery: facts are thenceforward shaken through a larger-meshed sieve. A few general considerations, and we have done. There is no centre for memory in the brain. The facts which we remember are not stored as in a box, nor can one imagine how they could be, considering that the physical basis of an idea is molecular change. The whole nervous system is probably concerned in memory, a particular change, which has momentarily occurred in its tissues, being more likely to occur again under certain circumstances than a fresh one, and certain tracks becoming well beaten and more permeable than others. Pleasure and pain are other general phenomena: they are not to be localized in the brain like vision or hearing. Pleasure is the consciousness that the whole body is under favourable conditions; and pain, the knowledge that the protoplasm of certain cells of the body is being acted upon by injurious agents, chemical or physical. There seems to be good evidence that separate nerves convey impressions of injury, distinct from those of touch and temperature; but it is the revolt of the whole body against conditions affecting a part which constitutes pain. Amidst the maze of perplexities which lies between physiology and psychology, there is, however, one fact which stands out clear and bold: the brain can create nothing. We have seen how matter is taken into the body and matter is cast off from the body. We have seen how energy is released in the body from chemical compounds, and made use of by the body. So now, after a moment’s thought, it must be plain that every stimulus which goes to the brain must have its effect there, and that a man’s thoughts and conduct are entirely dependent on what has, at some time or other, come in from the external world. The association centres can evolve wonderful thoughts, but they are structurally derived from the grosser sense organs, and must get all the material they work upon from them.