The foregoing examples of the employment of taus in upright and reversed positions is, however, by no means exhaustive. Fig. 41 teaches that the familiar checker-board or tartan design, symbolically employed in ancient Mexico, was the simple result of taus in contraposition, the square spaces thus found being alternately filled with black and brown or gray. The symbolism of this design only becomes evident when all the combinations in which it occurs have been carefully studied. It is represented in the Codices in the doorways and arches of certain sacred edifices which are shown to be estufas or temaz-calli by further illustrations which I could not reproduce here, but which exhibit even the steam escaping from the building and other unmistakable features. [Illustration.] Figure 41. Sahagun has recorded how these semi-sacred edifices were specially consecrated to the “Mother of the gods and of us all, whose curative and life-giving power was exerted in the temazcalli, also named xochicalli, the place where she sees secret things, rectifies what has been deranged in human bodies, fructifies young and tender things, ... and where she aids and cures....” It was customary for pregnant women to resort to these baths under the care of the medicine-woman who exhorted her patient on entering, with the words: “Enter into it, my daughter, enter into the bosom of our Mother whose name is Yoalticitl ... warm thyself in the bath, which is the house of flowers of our god ...” (Historia, book VI, chap. XXVII). The Vienna Codex contains, besides pictures of temples (fig. 41, _a_ and _b_), two instances which elucidate the meaning of the design; _c_ of the same figure displays the conventional symbol for land, fringed on three sides. Enclosed in this and seen, in profile, is a stratum of checker-board design, above which is a sheet of water; d displays a conventionally drawn mountain, inside of which is the symbolical vase filled with the design. From this steam or smoke ascends through the soil of the mountain, and forces its way through the surface, above which we see two recurved puffs of smoke and a young blossoming maize shoot, conventionally drawn, such as may be seen worn by priestesses, as a symbolical head decoration, on page 11 of the Vienna Codex. The seated figure of a priest is represented as sheltering its growth with his outspread mantle. On his back he displays a symbol, composed of two rolls united by a crossband, which is met with in Maya and Mexican Codices. In the latter the four projecting ends are usually painted with the colors of the four quarters. As these are figured as united into a single sign, it seems evident that this symbolized a union of the four elements deemed necessary for the production of life by the ancient native philosophers.