Another passage of Tacitus is decisive. There he says: "The mother's brother regards his nephew as his son; some even hold that the bond of blood between the maternal uncle and the nephew is more sacred and close than that between father and son, so that when persons are demanded as securities, the sister's son is considered a better security than the natural son of the man whom they desire to place under bonds." Here we have a living proof of the matriarchal, and hence natural, gens, and it is described as a characteristic mark of the Germans.[28] If a member of such a gens gave his own son as a security for the fulfillment of a vow and this son became the victim of his father's breach of faith, that was the concern of the father alone. But when the son of a sister was sacrificed, then the most sacred gentile law was violated. The next relative who was bound above all others to protect the boy or young man, was held responsible for his death; either he should not have given the boy in bail or he should have kept the contract. If we had no other trace of gentile law among the Germans, this one passage would be sufficient proof of its existence. But there is another passage in the Old Norse song of the "Dawn of the Gods" and the "End of the World," the Voeluspa, which is still stronger evidence, because it is 800 years younger. In this "Vision of the Seeress," in which Bang and Bugge have now demonstrated the existence of Christian elements, also, the description of the time of general degeneration and corruption inaugurating the great catastrophe contains this passage: Broedbr munu berjask ok at boenum verdask Munu systrungar sifjum spilla. "Brothers will wage war against one another and become each other's murderers, and sisters' children will break the bonds of blood." Systrungr means the son of the mother's sister, and an abnegation of the blood kinship from that side surpasses in the eyes of the poet even the crime of fratricide. There is a deliberate climax in that systrungar, emphasizing the maternal kinship. If the term syskina-boern, brother's and sister's children, or syskina-synir, brother's and sister's sons, had been used, there would have been a weakening of the effect, instead of a climax. That shows that even at the time of the Vikings, when the Voeluspa was composed, the recollection of maternal law was not yet blotted out.