Public safety is construed by the ruder type of man not so much in terms of freedom from physical danger--unless such a danger, the onset of another tribe, for instance, is actually imminent--as in terms of freedom from spiritual, or mystic, danger. The fear of ill-luck, in other words, is the bogy that haunts him night and day. Hence his life is enmeshed, as Dr. Frazer puts it, in a network of taboos. A taboo is anything that one must not do lest ill-luck befall. And ill-luck is catching, like an infectious disease. If my next-door neighbour breaks a taboo, and brings down a visitation on himself, depend upon it some of its unpleasant consequences will be passed on to me and mine. Hence, if some one has committed an act that is not merely a crime but a sin, it is every one's concern to wipe out that sin; which is usually done by wiping out the sinner. Mobbish feeling always inclines to violence. In the mob, as a French psychologist has said, ideas neutralize each other, but emotions aggrandize each other. Now war-feeling is a mobbish experience that, I daresay, some of my readers have tasted; and we have seen how it leads the unorganized levy of a savage tribe to make short work of the coward and traitor. But war-fever is a mild variety of mobbish experience as compared with panic in any form, and with superstitious panic most of all. Being attacked in the dark, as it were, causes the strongest to lose their heads. Hence it is not hard to understand how it comes about that the violator of a taboo is the central object of communal vengeance in primitive society. The most striking instance of such a taboo-breaker is the man or woman who disregards the prohibition against marriage within the kin--in other words, violates the law of exogamy. To be thus guilty of incest is to incite in the community at large a horror which, venting itself in what Bagehot calls a "wild spasm of wild justice," involves certain death for the offender. To interfere with a grave, to pry into forbidden mysteries, to eat forbidden meats, and so on, are further examples of transgressions liable to be thus punished. Falling under the same general category of sin, though distinct from the violation of taboo, is witchcraft. This consists in trafficking, or at any rate in being supposed to traffic, with powers of evil for sinister and anti-social ends. We have only to remember how England, in the seventeenth century, could work itself up into a frenzy on this account to realize how, in an African society even of the better sort, the "smelling-out" and destroying of a witch may easily become a general panacea for quieting the public nerves.