1885.] The Relations of Mind and Matter. 759 
their way at all through the ganglia. A new sensory current 
may in some animals pass onward and produce motion. In 
others it may fail to reach the muscles. Natural selection would 
act here also, and might preserve the individuals which failed to 
respond to this sensation. Thus in a single animal some sensa- 
tions will ‘come to produce a certain motor response, other sensa- 
tions another response, and still other sensations no response, and 
only the individual which is affected in just this manner can sur- 
vive, since any other series of movements or non-movements 
would cease to be protective. Such an animal would be a cor- 
rectly adapted reflex organism. No conscious or psychic powers 
would be necessary for its preservation. 
The repression of the sensory current by the ganglia is proba- 
bly a developmental characteristic of animal life. It only became 
necessary when sensation became active and abundant motor 
energy penetrated the body. It was absolutely necessary for the 
good of the economy that every sensation should not produce a 
motion, and the original nerve cells developed into ganglia, partly 
through this need of repression. These checked the great mass 
of the motor impulses, only permitting familiar ones to follow 
their ordinary channels. Yet such repression was not an intelli- 
gent one. It was largely governed, in fact, by the comparative 
vigor of the current. The principle seems to be that every sen- 
sory current, if sufficiently vigorous, may make its way through 
the gangliar resistance and affect the muscles. But currents of a 
special kind, which have already established a familiar channel, 
need less vigor to make their way through the ganglia, though 
even these are checked if very feeble. Finally special currents 
which have been repeated a great number of times may make 
their way onward even if very feeble. And in every case an 
abnormally strong current, even if it be of a kind that has estab- 
lished a familiar channel, will force itself to some extent upon 
other nerves and produce general and indefinite motions. This is 
the material out of which natural selection chooses its new adap- 
tations. Finally a nervous organism thus specially adapted to 
Surrounding conditions may be hereditarily transmitted, and a 
special series of reflex actions or resistances become inherent in 
the species. 
The next question to be considered is, that of the disposition 
of this repressed current energy. So far, in accordance with the 
, 
