316 THE AMERICAN NATURALIST. [Vou. XXXIII. 
would be for us if our feet were insensible. We can under- 
stand this easily, because we are able at any time to bring the 
sensations of touch and pressure in the sole of the foot before 
our consciousness. 
Far more important, however, are sensations of whose exist- 
ence many men know absolutely nothing, namely, those from 
the joints, tendons, and muscles. By the nerves from these 
organs the brain receives information in regard to their condi- 
tion, but this takes place in such a way that these sensations do 
not generally overstep the threshold of consciousness. They 
serve almost exclusively automatic purposes, and would there- 
fore unduly and uselessly burden our attention. But it is an 
established fact that we may be conscious of the muscular sense. 
We are conscious, for example, of the strength, the exertion 
which is required to lift a weight; indeed, we can estimate the 
weight of the object lifted by the strength expended, and dis- 
tinguish the heavier object from the lighter. For this reason 
the muscular sense has also been called the strength sense. 
The pains of fatigue, or the strong muscular pains caused by 
cramps, are perceived by means of the same nerve tracts. 
There are many who deny the existence of a muscular sense ; 
for example, Wundt. He prefers to refer whatever is ascribed 
to this sense to the sensations of the central nervous system. 
But many facts, especially pathological conditions, incline us to 
admit a muscular sense. 
Having now become acquainted with the existence of the 
muscular sense, we can comprehend that in this region we 
must seek the most important sensations which render possible 
the coérdination of the muscles and standing erect. 
The great significance which the joints and joint nerves 
attain in this process as a result of their position is self-evident. 
But these stimuli, transmitted from the locomotor apparatus, 
that is, the muscles, joints, tendons, etc., to the central nervous 
system, may perhaps be utilized in another way for the coördi- 
nation of the muscles. E. Hering proposes the following: At 
each slightly energetic movement, for example the bending of 
the arm, those muscles which produce the opposite movement— 
the antagonistic muscles, in this case the extensor muscles of 
