Page:Popular Science Monthly Volume 31.djvu/624

606 . . . She kneels, falls face forward to the ground, where she remains for hours in the attitude of crucifixion. Other attitudes are taken during the ecstatic condition, which comes to an end in the midst of alarming symptoms of impending death."

I will, in conclusion, venture upon a few suggestions as to the explanation of the phenomena of hypnotism and its allied states.

Our cerebral life depends upon the associated activity of innumerable nerve-cells grouped into clusters or centers, each center being more directly related with some sensory or some motor function. Thus there are visual centers, auditory centers, tactile centers, which form the terminal stations of the nerve-fibers leading from the organs of sight, hearing, and touch. There are also so-called motor centers, the nervous discharges from which, traveling down to the spinal cord, determine movements of the head, trunk, and limbs.

A network of the finest nerve-fibrils of astounding complexity brings the individual cells of each center into relationship with one another, and with the cells of the other centers. This physical association of our brain-elements is the material substratum of the psychical process of association of ideas which forms the groundwork of our intellectual life. All the higher manifestations of mind are correlatives of the harmonious co-operation of numerous brain-elements. Even what appear to be simple states of consciousness are often the result of association. Hence any disturbance in the mutual equilibrium of the cerebral centers speedily leads to alterations of those resultants of forces of which perception, thought, will, emotion, are the subjective manifestations.

One of the most striking properties of the nervous system is that by which the activity of one portion may be arrested or prevented "inhibited" by the activity of another. To give a familiar instance, the action of the respiratory centers is suddenly inhibited by certain excitations of the sensory nerves, as we have all experienced on receiving the first splash of a cold shower-bath. In the cerebral sphere, inhibition of one tract by another is the mechanism which lies at the root of the higher exercise of our faculties."When we choose, for instance, or exercise will-power, the corresponding state of our nervous organism is one involving more or less complex inhibitions. The sense of moral effort is the subjective equivalent of powerful inhibitions of brain-tracts in a state of high tension. The power of mental concentration rests likewise upon similar inhibitions. When we attend closely to a sensory impression, or to a train of thought, the excitability of every part of the brain except that actually engaged in the act is diminished by an inhibitory action of the working portion. Thus, when we say that anger or fear paralyzes, we allude in very accurate language to the inhibitory influence which powerful emotion exercises upon the other cerebral functions.

I have said that physiological sleep can be induced by certain