The Nervous System and the Mind

Abstract

THE time may come when the psychological historian will be required to trace the genealogy and career of such terms as “molecular movement” “discharge,” “explosion,” “unstable matter,” as applied to mental operations, as well as the familiar expression “environment.” Whoever else may have contributed to their use, they will be traced back in the main to Herbert Spencer. When once the brain was recognized as the organ of mind in a special sense, chiefly through phrenological observations in which Mr. Spencer was himself at one time engaged (he was, if we mistake not, a member of the London Phrenological Society), the physical basis of mind was naturally described in terms applied to material bodies and employed in physics. The combination of atoms forming molecules being regarded as the fundamental element of the substance of the nervous system, molecular movements were correlated with mental operations. Every corpuscle in the gray matter of the convolutions of the brain was regarded as “a reservoir of molecular motion.” It followed that the destructive molecular changes of which the granular protoplasm in the corpuscles is the seat were accompanied by a disengagement or discharge of motion. For the purpose of decomposition or waste, the amount of which is the measure of the force evolved, the remarkable supply of blood received by the cerebral convolutions was seen to be necessary; as also for the recomposition or repair which succeeds waste. Spencer drew some of his analogies from chemical explosions, taking for instance the explosion of the percussion cap and powder in a pistol to symbolize the setting up of decomposition in an adjacent ganglion-cell by (in the case of the retina) a disturbed retinal element. He showed that a partially-decomposed ganglion-cell propagates a shock through the afferent nerve to a large deposit of “unstable matter”in the optic centre, “where an immense amount of molecular motion is thereupon disengaged.” The transmission of waves of molecular motion through nerve-fibres is compared by Spencer to “a row of bricks on end, so placed that each in falling knocks over its neighbour. … Each brick, besides the motion it receives, will pass on to the next the motion it has itself gained in falling”

The Nervous System and the Mind: a Treatise on the Dynamics of the Human Organism.

By Charles Mercier (London: Macmillan and Co., 1888.)