difference to the earliest settler between the benevolent spirits of the reclaimed clearing and the hostile spirits of the wild woodland has never been quite fully appreciated. But this device was one to which you need only have recourse on a particular occasion; the permanent difficulty was to mark off your cultivated land from the forest and its dangerous spiritual population, in some way by which the latter might be prevented from making itself unpleasant. You must draw a definite line between good spirits and bad, between white spirits and black. Here it is that we find the origin of a practice which lasted all through Roman history, passed on into the ritual of the Church, and still survives, as at Oxford on Ascension Day, in the beating of parish bounds. The boundary of the cultivated land was marked out in some material way, perhaps by stones placed at intervals, like the _cippi_ of the old Roman _pomerium_, from the woodland lying around it; and this boundary-line was made sacred by the passage round it (_lustratio_) at some fixed time of the year--in May as a rule, when the crops were ripening and especially liable to be attacked by hostile influences--of a procession occupied with sacrifice and prayer. I must dwell for a moment on this procession as it is described by old Cato; but at this point I may just interpolate the remark that the object of its mysterious influence was the arable land only and the crops.[120] The sheep and cattle were otherwise protected, when, after their seclusion within the boundary during the winter, they were driven out in April to pasture beyond it, where they would be in far greater peril from enemies spiritual and other. If you wish to see how this was done, read Ovid’s account of the Parilia in the fourth book of his _Fasti_, and Dr. Frazer’s illuminating commentary on it (St. George and the Parilia) in the _Revue des Études Ethnographiques et Sociologiques_ for 1908, p. 1 foll.