Thus there is no question that the priests were chosen and separated from the people in such a way as to meet with the approval of the gods; and even the acolytes, _camilli_ and _camillae_, boys and girls who frequently appear in sacrificial scenes on monuments, wore the _toga praetexta_, and, in order to be acceptable, must be the children of living parents.[365] This rule has lately been the subject of a discussion by Dr. Frazer, on which he has brought to bear, as usual, a great range of learning. He regards the restriction not so much as a matter of good omen, _i.e._ of freedom from contamination by the death of a parent, but as pointing to a notion that they were "fuller of life and therefore luckier than orphans."[366] Whether or no this explanation is the right one, it is quite consistent, as we shall see directly, with the general idea of sacrifice at Rome, and the learning by which it is supported is in any case of interest and value. There is abundant evidence from historical times that all worshippers, and therefore _a fortiori_ all priests, when sacrificing, had to be personally clean and free from every kind of taint; a rule which also held good for the utensils used in the worship, which in many cases at least were of primitive make and material, not such as were in common use.[367] The need of personal purity is well expressed by Tibullus in his description of a rural festival[368]:-- vos quoque abesse procul iubeo, discedat ab aris cui tulit hesterna gaudia nocte Venus. casta placent superis: pura cum veste venite et manibus puris sumite fontis aquam.