Each of these four schools has preserved one or two recensions of the Yajurveda. The text of the Maitrayani Samhita, which consists of four books (kanda), subdivided into fifty-four lessons (prapathaka), has been edited by Professor L. v. Schroeder (1881-86). The same scholar is preparing an edition of the Kathaka Samhita, the recension of the Katha school. These two recensions are nearly related in language, having many forms in common which are not found elsewhere. Of the Kapishthala-Katha Samhita only somewhat corrupt fragments have hitherto come to light, and it is very doubtful whether sufficient manuscript material will ever be discovered to render an edition of this text possible. The Taittiriya Samhita, which comprises seven books, and is subdivided into forty-four lessons, is somewhat later in origin than the above-mentioned recensions. It was edited by Professor A. Weber in 1871-72. These texts of the Yajurveda form a closely connected group, for they are essentially the same in character. Their agreement is often even verbal, especially in the verses and formulas for recitation which they contain. They also agree in arranging their matter according to a similar principle, which is different from that of the Vajasaneyi recension. The Samhita of the latter consists entirely of the verses and formulas to be recited at the sacrifice, and is therefore clear (çukla), that is to say, separated from the explanatory matter which is collected in the Brahmana. Hence it is called the White (çukla) Yajurveda, while the others, under the general name of Black (krishna) Yajurveda, are contrasted with it, as containing both kinds of matter mixed up in the Samhita. The text of the Vajasaneyins has been preserved in two recensions, that of the Madhyamdinas and of the Kanvas. These are almost identical in their subject-matter as well as its arrangement. Their divergences hardly go beyond varieties of reading, which, moreover, appear only in their prose formulas, not in their verses. Agreeing thus closely, they cannot be separated in their origin by any wide interval of time. Their discrepancies probably arose rather from geographical separation, since each has its own peculiarities of spelling. The White Yajurveda in both these recensions has been edited by Professor Weber (1849-52).