The physiology and hygiene of the house in which we live . thebrain proper. For instance, we start off to walk. We areconscious of willing that our leg machinery should propel usforward, but once having started it we leave the rest of thework to the ganglionic and spinal nervous system, withoutgiving any thought to it until it is time for us to will to goin some other direction; then we telegraph to the ganglia tocarry us in that way, or stop, as the case may be, like the con-ductor and the fireman on a train. These ganglia, then, regulateautomatically the pressure of our feet and the proper c
The physiology and hygiene of the house in which we live . thebrain proper. For instance, we start off to walk. We areconscious of willing that our leg machinery should propel usforward, but once having started it we leave the rest of thework to the ganglionic and spinal nervous system, withoutgiving any thought to it until it is time for us to will to goin some other direction; then we telegraph to the ganglia tocarry us in that way, or stop, as the case may be, like the con-ductor and the fireman on a train. These ganglia, then, regulateautomatically the pressure of our feet and the proper contrac-tion and relaxation of all the muscles necessary for locomotionwithout our giving any conscious thought to it. Thisthcvdoby automatically regulating and controlling the proper nervesupply—or co-ordination, as we call it. Why, for instance, doesa babe put his spoon as often into hie ear as into his mouth ?Because hifl ganglia have not yet learned to co-ordinatehia muscles and to fore- them into work in harmony. And 9* 202 Physiology and so it would be with us in every action requiring more than asingle muscle, if it were not for these little insignificant knots of gray nervous takes away theirpower of co-ordination,and hence we see drunk-en men reel to and froand be at their witsend to know whichway to lean, or how tosit down without hold- Isolated ganglion cell from the anterior horn of the ing on ; and the mosthuman soher man in the world would be in like plight if it were not for these ganglia, whichact very much like the relays, I believe they call them, on atelegraphic circuit, which do so much of the work of trans-mission without requiring a conscious operator in their it is with our ganglia. If it were not for them we shouldbe tired to death merely trying to remember to keep is it that we never forget to breathe ? We certainlydo not think to do so every time. Why, these ganglia andrespiratory centers take t
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