For the ramifications of the nervous system penetrate to every part of the body, including the internal organs. From its seat of honour in the brain and spinal cord it sends its messages to every tissue in the body, and receives messages in return. It may be compared to an electric power station, which distributes its current to every part of a town. But with this difference, if the electric light in a house goes wrong, it does not affect the main station, whereas if any portion of the body however small or insignificant gives way, it adversely affects the central parts of the nervous system. And if the various sections and organs do not work together smoothly, the nervous system, which governs them all, suffers along with them. The nervous system suffers in two ways when the internal organs and other parts of the body fail to do their work properly. [Sidenote: Starvation.] First of all, it languishes from starvation. This does not mean that the individual is not taking sufficient quantity of food. He may be taking enough, even too much, but it is not being digested or assimilated satisfactorily, and though there is plenty of food there is a deficiency of nutriment. [Sidenote: Poisoning.] Secondly, it may suffer from poisoning. This may be the result of dyspepsia, for when food lies in the stomach undigested, it is apt to ferment, producing a poison that circulates throughout the body. Or it may be because the impurities, which are found throughout the whole body, are not being got rid of, owing to a want of exercise and fresh air. Or it may be owing to undue wear and tear in consequence of a lack of sufficient rest. Too often it is a combination of the two processes, the nervous system being attacked by starvation and poisoning at the same time. The whole of man’s structure is a marvellous automaton, and once the nervous element is disturbed the trouble which first upset the harmony is increased tenfold. [Sidenote: Compensation.] Yet the mischief may not be apparent all at once, for the whole organisation is so accurately balanced that defects in one part will be compensated for by other organs. And whilst this is a safeguard in one way, it is a serious menace in another. For the fault is apt to be overlooked, until at last the process has gone on to such an extent that the balance is upset. The machine does not stop running, but, like a motor-car in similar circumstances, it begins to run badly. The man himself becomes what is called “run down.” It is a provision of Nature that the nervous system, being the mainspring of our existence, holds out longer than any other structure in the body. If it did not do so most of us would have been dead or broken down long ago. Yet it means that when the loss of balance reaches such a point that compensation fails, the breakdown is all the more disastrous. [Sidenote: The cause of the breakdown.]