It is divided into forty chapters, called adhyayas. That it originally consisted of the first eighteen alone is indicated by external as well as internal evidence. This is the only portion containing verses and prose formulas (both having the common name of mantras) which recur in the Taittiriya Samhita, the sole exceptions being a few passages relating to the horse-sacrifice in chapters 22-25. Otherwise the contents of the last twenty-two chapters are found again only in the Brahmana and the Aranyaka belonging to the Taittiriya Samhita. Moreover, it is only the mantras of the first eighteen chapters of the Vajasaneyi Samhita which are quoted and explained word by word in the first nine books of its own Brahmana, while merely a few mantras from the following seventeen chapters are mentioned in that work. According to the further testimony of an ancient index of the White Yajurveda, attributed to Katyayana, the ten chapters 26-35 form a supplement (khila). The internal evidence of the Vajasaneyi Samhita leads to similar conclusions. The fact that chapters 26-29 contain mantras relating to ceremonies dealt with in previous chapters and requiring to be applied to those ceremonies, is a clear indication of their supplementary character. The next ten chapters (30-39) are concerned with altogether new ceremonies, such as the human sacrifice, the universal sacrifice, and the sacrifice to the Manes. Lastly, the 40th chapter must be a late addition, for it stands in no direct relation to the ritual and bears the character of an Upanishad. Different parts of the Samhita, moreover, furnish some data pointing to different periods of religious and social development. In the 16th chapter the god Rudra is described by a large number of epithets which are subsequently peculiar to Çiva. Two, however, which are particularly significant, Içana, "Ruler," and Mahadeva, "Great God," are absent here, but are added in the 39th chapter. These, as indicating a special worship of the god, represent a later development. Again, the 30th chapter specifies most of the Indian mixed castes, while the 16th mentions only a few of them. Hence, it is likely that at least some which are known to the former chapter did not as yet exist when the latter was composed. On these grounds four chronological strata may be distinguished in the White Yajurveda. To the fundamental portion, comprising chapters 1-18, the next seven must first have been added, for these two parts deal with the general sacrificial ceremonial. The development of the ritual led to the compilation of the next fourteen chapters, which are concerned with ceremonies already treated (26-29) or entirely new (30-39). The last chapter apparently dates from a period when the excessive growth of ritual practices led to a reaction. It does not supply sacrificial mantras, but aims at establishing a mean between exclusive devotion to and total neglect of the sacrificial ceremonies.