The content of mystic thought is determined by the individual character and level of culture possessed by each degenerate and hysteric. For we should never forget that the morbidly-affected or exhausted brain is only the soil which receives the seed sown by nurture, education, impressions and experience of life, etc. The seed-grains do not originate in the soil; they only receive in and through it their special irregularities of development, their deformities, and crazy offshoots. The naturalist who loses the faculty of attention becomes the so-called ‘Natural Philosopher,’ or the discoverer of a fourth dimension in space, like the unfortunate Zöllner. A rough, ignorant person from the low ranks of the people falls into the wildest superstition. The mystic, nurtured in religion and nourished with dogma, refers his shadowy impressions to his beliefs, and interprets them as revelations of the nature of the Trinity, or of the condition of existence before birth or after death. The technologist who has fallen into mysticism worries over impossible inventions, believes himself to be on the track of the solution of the problem of a _perpetuum mobile_, devises communication between earth and stars, shafts to the glowing core of the earth, and what not. The astronomer becomes an astrologist, the chemist an alchemist and a seeker after the philosopher’s stone; the mathematician labours to square the circle, or to invent a system in which the notion of progress is expressed by a process of integration, the war of 1870 by an equation, and so on.
As was set forth above, the cerebral cortex receives its stimuli, not only from the external nerves, but also from the interior of the organism, from the nerves of separate organs, and the nerve-centres of the spinal cord and the sympathetic system. Every excitement in these centres affects the brain-cells, and arouses in them more or less distinct presentations, which are necessarily related to the activity of the centres from which the stimulus proceeds. A few examples will make this clear, even to the uninitiated. If the organism feels the need of nourishment, and we are hungry, we shall not only be generally conscious of an indeterminate desire for food, but there will also arise in our minds definite representations of dishes, of served repasts, and of all the accessories of eating. If we, from some cause, maybe an affection of the heart or lungs, cannot breathe freely, we have not only a hunger for air, but also accompanying ideas of an uneasy nature, presentiments of unknown dangers, melancholy memories, etc., _i.e._, representations of circumstances which tend to deprive us of breath or affect us oppressively. During sleep also organic stimuli exert this influence on the cerebral cortex, and to them we owe the so-called somatic dreams (_Leibesträume_), _i.e._, dream-images about the functioning of any organs which happen not to be in a normal condition.