Page:Popular Science Monthly Volume 47.djvu/645

Rh organs of expression to the inner nerve centers, and that in many cases these are sufficient (even when induced by agencies which must be called external and fortuitous) to give a bias to the mind. When Mr. Du Maurier depicted a small child forcibly wagging the tail of a big St. Bernard in order to put it in a good humor, most people who laughed at the conceit probably thought that the child's plan was as illogical as that of moving the pointer of a barometer in order to bring about a change in the weather. But it will be seen, when we come to discuss these curious centripetal currents, that this is by no means the case. Indeed, in all probability, some of the mental peculiarities which mark the members of certain professions may be owing to changes which originated primarily in the features.

Leaving this subject for the present, let us pay attention to some of the face-making forces which act from within. In my previous article a good deal was said about the facial muscles, and the nervous mechanism which controls them. It was explained how a constant succession of stimuli to one set of muscles would, in the course of time, give them a predominant influence, and so bring about a general change of expression. Nowhere can such a result be seen better than in the horsey type above alluded to. Speaking generally, the expression of all men of action is attributable to like causes. In such people the chief motive force is the will, which is continually exerting authority over the man himself, or over other men or things. Hence we find that the expression mechanism which is under the control of the will (consisting chiefly of muscles of the striped variety) is mainly responsible for the result.

But a little reflection will show that the salient points of many of the typical faces which we constantly see are under but little obligation to these agents of the will. It is beyond the power of the facial muscles shown in works on anatomy to give a man a shiny nose or a double chin, or to affect the tint and general tone of the integument.

Such changes must be attributed to the influence of the sympathetic nervous system, which is practically independent of the will, and which profoundly influences growth and nutrition in all parts of the body. Any one who has looked into a treatise on physiology will have seen diagrams of the sympathetic nervous system, and will have learned that nearly all unconscious organic processes, such as the digestion and assimilation of food, the movements of the heart, the alteration in the caliber of the arteries, and the special functions of innumerable glands, are carried on under its management. He will also have learned that fibers from the sympathetic ganglia frequently join the nerve trunks derived from the brain and spinal cord; and that