To complete our picture of the patriarchal family, we have the traditions of three distinct customs or rites affecting its internal economy. Two of these rites, the maintenance of the sacred house-fire, and the marriage ceremony, probably date back to a very remote period; and the third, the custom of adoption, though of later development, may be regarded, in its origin at least, as primitive. Fire is itself so wonderful in its appearance and effects, so good a servant, so terrible a master, that we cannot feel any surprise at its having attracted a great deal of attention in early times. The traces of fire-worship are so widely spread over the earth that there is scarcely a single race whose traditions are entirely devoid of them. But the sacred house-fire of the Aryans is interesting to us chiefly in its connection with other family rites in which it played an important part. This fire, which was perpetually kept burning on the family hearth, seems to have been regarded in some sort, as a living family deity, who watched over and assisted the particular family to which it belonged. It was by its aid that the food of the family was cooked, and from it was ignited the sacrifice or the funeral pyre. It was the centre of the family life; the hearth on which it burned was in the midst of the dwelling, and no stranger was admitted into its presence. That hearth was to each member of the household as it were an _umbilicus orbis_, or navel of the earth--_hearth_, only another form of _earth_.[53] When the members of the family met together to partake of their meals, a part was always first offered to the fire by whose aid the meal was prepared; the patriarch acted as officiating priest in this as in every other family ceremony; and to the patriarch’s wife was confided the especial charge of keeping the fire supplied with fuel. [Sidenote: Marriage.]