Why? The Science of Athletics

I I 6 WHY?-THE SCIENCE OF ATHLETICS Nerves Supply Human Tele– graph System Nerves link up every part of our organism, just as telegraph wires maintain communi– cation betwe~n all towns, and practically all villages, in every civilized country. We have central stations in the brain, the spinal column and other ganglions. We have also a postal system in which certain of our organs discharge chemicals (hormones) into the blood stre.am to act as messengers to distant parts, but this system, although serving its own useful pur.pose, is too slow for the demands of that now highly specialized animal, Man. And . so we have developed a species of reflex, telegraphic action by which, to take a simple case, when we experience externally inflicted pain, a nerve-thrill conveys ·an S 0 S for action and a return thrill brings the order to t he muscles for the movement which will remove the afflicted part from the source of external interference. That is why a person jumps when you stick a pin into him. By reflex action is meant action without conscious effort, such as we spoke of in Chapter Three, when mention was made of the athlete under strain partly or wholly closing his lids to protect the fine blood-vessels of the eye. Practically the whole of a man's body is linked up by this kind of automatic nerve machinery, operating generally through the spinal column, or the nerve centres of the brain. Slowly but surely physiologists are discovering more and more secrets of our nervous systems ; but as yet they do not know the nature of the nerve thrills, -or impulses, to which reference · has been made · already. Experiments with injured and uninjured nerves connected up to a delicate electrical measuring instrument have - shown that an electric current passes from tpe injured to the uninjured point, and the same instrument reveals some small electrical change when messages are passed. From this it would appear that although electric waves pass along the nerves, the nerve thrills are not themselves electric · waves, · alt~ough they are accompanied by