110 NEW BOOKS. Laughing, like dreaming, is also found to correspond to a temporary state of mental disorder, which is beneficial rather than harmful : in the mental state from which laughter issues the will is again in abeyance, and with it the moral sense is affected. Laughter does not always, or even generally, proceed from a purely joyous state : there is more often a touch of malice, or of meanness, or the like, in the feeling which excites it. Sir Arthur finds the phenomenon of laughter, i.e., the physical movements in which the mental state is expressed, inexplicable, as also the fact that precisely the same physical expression may be produced by the act, or even by the threat of tickling. The two sets of phenomena cannot be distinguished from one another, yet the one is pleasant and its continuance desired, the other unpleasant, and its continuance avoided. Perhaps the author sets them in too strong contrast one with another. It is hardly true, e.g., that " the laughter which follows tickling is not the expression of a mental state coincident with, or antecedent to, the act of tickling. It is induced by a physical operation " (p. 51). After all, the laughter does not ensue unless the tickling is felt ; it is a reaction to a certain sensation-mass, and may be called the expression of that mental state : on the other hand, it is at least not unreasonable to find an analogy between the sensation of tickling and the feeling which arises on the perception of a ridiculous scene. Again, the effect of inhaling nitrous oxide mixed with air, which Sir Arthur regards as a third and distinct kind of laughter, may be only an indirect effect of the gas. The latter may paralyse the control-centres of the laughter-reflex, so that laughter ensues upon the slightest sensation. We are all aware of moods in which laughter arises far out of proportion to the cause. In this article there are some useful notes on the natural history of laughter : its occurrence in animals, in man at different ages, in the blind, in blind- deaf mutes, etc. Blushing offers perhaps the most inexplicable phenomenon of the three : it has no apparent raison d'etre, serves no purpose that we can discover in the economy of life ; yet it is universal in man, is unlearned, for it occurs in the born-blind, and in blind-deaf mutes, and it also can be produced by the action of a special drug. Here again we have, according to Sir Arthur, a mental disorder, which, although not perhaps beneficial, at least does not harm the subject ; but in this case the dis- order follows rather than causes the physical appearances. The mental state of which blushing is the outcome is said to be shame at the ob- servation by others of some, real or supposed, unbecoming action on our part. But is there not a blush of surprise, of sudden joy ? Perhaps the true mental correlative of the blush has still to be defined. It suggests to the author that possibly every mental state has some correlative physical outcome of a definite kind, although not necessarily on the sur- face of the body, while conversely every bodily state has probably its special mental correlative. Some interesting illustrations are given from his experience of insanity. J. L. MdNTYRE. Primitive Traits in Religious Revivals : a Study in Mental and Social Evolution. By FREDERICK MORGAN DAVENPORT. New York and London : Macmillan & Co., 1905. Pp. 323. Prof. Davenport holds that religious movements of magnitude have often assumed a mode which has been termed sympathetic likeminded- ness, and the predominant mental characteristics of a population under its influence are suggestibility, imitativeness, imagination, and emotion.
