What are known as ganglia, or tiny bunches of nerve cells, are found in various parts of the nervous system, including the spinal nerves. These groups of nerve cells are sometimes called "little brains," and perform quite important offices in the mechanism of thought and action. The spinal ganglia receive sensory reports, and issue motor impulses, in many cases, without troubling the central brain regarding the matter. These activities are known as "reflex nervous action." REFLEX ACTION. What is known as reflex nervous action is one of the most wonderful of the activities of the nervous and mental mechanism, and the knowledge thereof usually comes as a surprise to the average person, for he is generally under the impression that these activities are possible only to the central brain. It is a fact that not only is the central brain really a trinity of three brains, but that, in addition to these, every one has a great number of "little brains" distributed over his nervous system, any and all of which are capable of receiving sensory reports and also of sending forth motor impulses. It is quite worth while for one to become acquainted with this wonderful form of neuro-mental activity. A cinder enters the eye, the report reaches a ganglion, a motor impulse is sent forth, and the eyelid closes. The same result ensues if an object approaches the eye but without actually entering it. In either case the person is not conscious of the sensation and motor impulse until the latter has been accomplished. This is reflex action. The instinctive movement of the tickled foot is another instance. The jerking away of the hand burnt by the lighted end of the cigar, or pricked by the point of the pin, is another instance. The involuntary activities, and those known as unconscious activities, result from reflex action. More than this, it is a fact that many activities originally voluntary become what is known as "acquired reflexes," or "motor habits," by means of certain nervous centers acquiring the habit of sending forth certain motor impulses in response to certain sensory reports. The familiar movements of our lives are largely performed in this way, as, for instance, walking, using knife and fork, operating typewriters, machines of all kinds, writing, etc. The squirming of a decapitated snake, the muscular movements of a decapitated frog, and the violent struggles, fluttering, and leaps of the decapitated fowl, are instances of reflex action. Medical reports indicate that in cases of decapitation even man may manifest similar reflex action in some cases. Thus we may see that we may _feel_ and _will_ by means of our "little brains" as well as by the central brain or brains. Whatever mind may be, it is certain that in these processes it employs other portions of the nervous system than the central brain. THE THREE BRAINS.