Читать книгу The Pelman System of Mind and Memory Training - Lessons I to XII - Анон - Страница 20

14. “But,” you may object, “I earn my living with my hands, not with my brain.” This is a mistaken idea, whatever your occupation. The miner traces his seam and directs his pick with his brains; the ploughman plans his furrow with his brains; the drover is constantly estimating and circumventing with his brain the erratic movements of his herd; the engine-driver is studying steam-pressures and gradients and loads; the chauffeur has ever his brain on the alert for the problems of traffic; the carpenter must have some mental knowledge of the laws of stress; the bricklayer must exercise judgment in the placing of his bricks. In addition to the direct action of the brain in such employments, there is also an indirect action, and a trained brain finds its reflection in a more ready acquisition of manual dexterity.

When certain portions of the brain, known as motor centres, are injured, paralysis of the body ensues. If you inadvertently touch with your fingers something that is very hot, you immediately and “instinctively” draw back your hand. The action of withdrawal may appear instantaneous, but what actually happened is that the sensation of excessive heat travelled from your finger-tip to your brain, and your brain has sent back to the muscles of your arm, hand and finger, a message and impulse to remove the finger from that which is causing the pain. In the case of certain diseases, interruptions may occur in the course of the transmission of these nervous and muscular messages. All this demonstrates the influence exerted by the brain over the rest of the body. Later, we shall see evidence of influences exerted by the body at large upon the brain in particular. The point to be grasped at present is that the brain is the directing power.