As said before, one of the principal functions of the priesthood was the exercise of the art of divination, and the principal instrument was the tonalamatl. The priests of Tlazolteotl were supposed to be especially expert in the use of the “book of days”; the horoscopes of new-born children were invariably cast, and a favourable day selected for the baptismal ceremony (as described below, p. 160), in accordance with the various influences attached to the day of its birth. Constant recourse was had to the interpreters of the tonalamatl in almost every emergency, and practically no enterprise of importance was undertaken except upon a propitious day. But there were numerous other methods of divination, and several grades of magical practitioners. Grains of maize or red beans were commonly employed to discover the issue of a sickness. The goddess Tozi was the patroness of the professional magicians who used this means, though the casting of the grains was usually performed in the presence of a figure of Quetzalcoatl, the arch-patron of magic. Twenty grains were usually cast upon a cloth; if they fell forming a hollow circle, typifying a grave, it was believed that the sick person would die; but if so that a straight line could be drawn leaving ten on each side, the patient would recover. Or again, if they fell scattered, a fatal termination to the illness was expected; but if in a heap, health would be restored. At Tlaxcala it was a fatal sign if one grain stood up on end. Grain was also used in divination by the Mixtec, who sowed seed on the nemontemi days, and from its success or failure calculated the prospects of the year’s crop. Another method of prognosticating the chances of a patient consisted in winding a string into a knot; if it could be pulled loose, the patient would recover, otherwise his chances were small. Or again, a sick child would be held over a vessel of water, and his reflection carefully observed; if the image was dim there was small prospect of recovery. The last method of divination was employed when the sickness was supposed to be due to absence of the child’s _tonalli_ (which may be translated “soul” or “luck”), and constitutes another instance of the belief, so common throughout the world, that the incorporeal nature of man is closely connected with his reflection or shadow. Snakes were also used in divination, especially to discover a stolen object; the suspected persons were seated in a circle, and the magician placed a basket containing a snake in the middle. The basket was uncovered, and it was believed that if the culprit were present the snake would indicate the fact by crawling to him. Scrying in a mirror or bowl of water was another method of divination widely employed in Mexico proper, and was found among the Tarascans also. At Tlaxcala a peculiar custom was observed when war was declared in order to estimate the chances of ultimate success. Two sacred arrows were carefully kept