Page:Popular Science Monthly Volume 38.djvu/255

Rh of the minor degree as all unite to trick those outside. And the reason is this: the half-dozen members of the most secret rank profess to one another that no better system of governing a savage community could be devised than this ceremonial mystery of the Duk-duk.



LL our sensations, from the most trifling pleasure to the highest delight, from the hardly perceptible discomfort to the keenest anguish, the whole gradation of manifold variations of feeling, originate from the propagation of excitations from without through the nerves to the central organ of the nervous system and to consciousness. The nerves are the conductors of the stimulus-waves which go to the nerve cells of curious terminal forms in the brain and spinal marrow; and every excitation that touches any part of those conductors releases a sensation, the pleasant or unpleasant character of which depends first upon its intensity. To a certain degree every moderately strong excitation affecting us is agreeable and begets a feeling of pleasure rising to lively delight. An excitation surpassing this limit calls out an uncomfortable feeling which passes into pain. A gentle stroking of our skin, for example, is enjoyed; a strong pressure upon it evokes an uncomfortable feeling, which, continuing, passes into pain. Harmonious musical tones please our ears, but discordant noises make us miserable.

That a stimulus striking the sensitive nerves should reach our consciousness as a pain depends not on the force of the attack only, but also on the delicacy of the nervous system, which varies with different men to a considerable degree. Thus, many persons having finely developed organs of those senses can smell and taste many things of which other persons can hardly conceive; and much that is painful to an over-delicate lady causes no inconvenience to the hardy, coarse rustic. Also in various conditions of disordered health the whole nervous system or part of the sensitive nerves suffers from excessive sensitiveness, in consequence of which insignificant affections cause agony.

Neuralgias, or pains in particular nervous tracts, may be brought about by various causes by disease in the terminal ramifications of the nerves, from disorders in the nerve-stem, through illness of the brain or spinal marrow, or from some irritation affecting another distant nerve, transmitted to this one through the central nervous system by what is called a reflex process. The common expression, "nervous pain," conveys no distinction respecting the character or source of the affection; but to the 