Not long after the time when the commentaries on the Vedas, or Brahmanas, arose in the schools of the Brahmans, a fourth Veda was added to the three collections of sacred songs and prayers already in existence. Ancient poems were preserved which had not been received into the Rigveda. These were not songs of praise or thanksgiving, prayers or sentences intended to accompany the sacrificial acts, but charms to avert evil, danger, sickness, or death, formulæ relating to life in the house and family, bringing blessing or a curse. When the fourth superintending priest was added to the three already officiating, and the latter was charged with the office of avoiding the mistakes which might be committed in it, and atoning for those which had been committed by counter-charms and acts of expiation--a collection of the sentences required, a book of prayers, seems to have been given to this priest also, just as the Hotar had his Rigveda, the Udgatar his Samaveda, the Adhvaryu his Yajurveda. Thus the sentences of this kind already living in tradition may have been collected together, so as to form a fourth Veda. That some of the exorcisms and incantations belonging to this collection are also found in the Rigveda, that meditative hymns of later date are received into the fourth Veda together with pieces of very great antiquity, may count rather for than against this mode of origin. The new collection was called the Atharvaveda after the ancient priest Atharvan, who is said first to have enticed the fire from the pieces of wood.[351] The Atharvaveda contains a number of ancient charms against sickness and death. It is the healing powers of waters and plants which are first invoked for assistance. In the Rigveda also all remedies are found in waters and plants, both of which come from the sky.[352] "May the waters of Himavat be blessed for thee," so we are told in the Atharvaveda; "the waters of the springs, the waters of the rain, the waters of the steppe, the waters of the cisterns, the waters of the pitchers. We bless the best healers, the waters. The waters should heal thee when pain overcomes thee; they should drive out thy sickness."[353] Plants are not less efficacious. They pass into the limbs of the sick, they expel the sickness victoriously from the body, they unite with their king Soma in order to fight against the sickness; they obey the voice of the priest, rescue the sick person from pain, and set free the foot of man from the toils of Yama.[354] The Atharvaveda emphasises the peculiar healing power of a plant against the Rakshasas (the evil spirits); with this Kaçiapa, Kanva, Agastya, and the son of Atharvan had defeated the Rakshasas. "Liberate," so the priest says to it, "liberate this man from the spirits of the Rakshasas; lead him back into the company of the living."[355] In other sentences of this Veda we are told: "With this sacrificial butter I liberate thee, so that thou mayest