1885. ] The Relations of Mind and Matter, 761 
yields a specialized effect for every special mode of sensation, and 
that this effect is permanent, the phenomena of memory prove. 
And no such effect can be produced by motion upon substance 
except it take part in the organization of that substance. Motion 
otherwise related to substance must flow out and disappear. Only 
the motion to which formation is due persists in any aoe or 
organized mass. 
Possibly every ganglion has its memory. But it is much more 
probable that in the continued development of the nervous sys- 
tem, as superior or more centralized ganglia originated, the 
function of the lower ganglia became simply distributive, and 
they ceased to exert a repressive influence upon the current. 
Thus in a vertebrated animal, for instance, it is not im- 
probable that the discriminative power of a spinal ganglion lies 
between its sending a sensory current directly to some muscle or 
sending it upward towards the cerebrum. It is a question of 
office. To the extent that reflex action has been established in 
the Vertebrata this short circuiting is the method pursued. It is 
the normal method in the sympathetic nerves, whose current 
makes its way to more and more central ganglia only as it grows . 
in strength or becomes unusual in character. It is the method in 
many of the cerebro-spinal nerves for actions that have become 
habitual, like those of walking, for instance. Only when the 
regularity of step is in some way interfered with does the sensory 
current force its way to the cerebrum and arouse conscious- 
ness. 
In nerve development, then, an early stage is the appearance of 
the ganglion with its discriminative and repressive powers and its 
memory record. A later stage is the appearance of several gan- 
glia, one more central to the whole nervous system than the 
others. In this case, as we may conceive, the function of the in- 
ferior ganglia becomes confined to discrimination between send- 
ing a sensory current directly to the muscles or onward to the 
central ganglion. The power of final decision and repression of 
the current may be confined to the latter, and it may become the 
sole seat of memory. This centralization makes continuous pro- 
gress through the lower life forms. It is clearly indicated in the 
insects, yet here it is doubtful if it has gained ascendency over 
reflex action, to which the great mass of insect motions seem due. 
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