1885.] The Relations of Mind and Matter. 681 
enter the body through a specially organized nerve apparatus, 
the rods and cones of the eye. But they all, as radiant heat, 
enter at every part of the surface, by aid of less specialized nerve 
endings. Heat in another condition, the static vibrations of con- 
tiguous matter, also enters at every part of the surface, presuma- 
bly through the same channel. A second series of vibrations, 
those of ponderable matter, enter by the channel of the ear, 
through the aid of an intricately organized apparatus. In addi- 
tion to these three conditions of vibratory influence there are 
three modes of direct contact through which motor energy also 
makes its way into the body. These are solid, liquid and gase- 
ous contact. Gaseous contact enters by a special channel, that of 
the nerves of smell, which are excited by the touch of excessively 
fine material borne on the air current. Liquid contact finds its 
special channel in the nerves of taste, which are only sensitive to 
the direct touch of liquified or dissolved matter. Solid contact 
has the whole surface for its field. The nerves of touch, indeed, 
are also sensitive to liquid and gaseous contact if exerted by mat- 
ter in motion, but mainly respond to the contact and pressure of 
solid matter. 
The internal extremities of. the nerves lack the variety of their 
surface endings. They are distributing organs as the latter are 
receiving organs. The energy received varies greatly in charac- 
ter, and needs considerably varied apparatus for its reception. 
That distributed has become far more homogeneous and can be 
dispersed by a single apparatus. This is the muscle fiber, which, 
though not ordinarily considered so, is essentially but a nerve 
ending, an aggregation of unstable chemical molecules around 
the extremity ofa nerve. And the combined aggregates of these 
bers, which constitute a muscle, are but a mass of nerve extrem- 
ities ending in matter which is adapted to set free a considerable 
volume of motor energy. Into this matter the energy which 
has traversed the nerves is discharged, and there instigates an 
active chemical change and a rapid freeing of energy, with animal 
motion as its result. 
Such is reflex action, a frequent mode of nerve action in man, 
and possibly the only one in many of the lower animals. Motor 
_energy differing greatly in character and source is thus forced to 
produce a single effect, that of muscular contraction and animal 
1See Organic Physics, AMER. NAT., Feb., 1883. 
