As a syllable could be expressed by any object whose name commenced with it, as few words can be given the form of a rebus without some change, as the figures sometimes represent their full phonetic value, sometimes only that of their initial sound, and as universally the attention of the artist was directed less to the sound than to the idea, the didactic painting of the Mexicans, whatever it might have been to them, is a sealed book to us, and must remain so in great part.

Moreover, it is entirely undetermined whether it should be read from the first to the last page, or _vice versa_, whether from right to left or from left to right, from bottom to top or from top to bottom, around the edges of the page toward the centre, or each line in the opposite direction from the preceding one.

There are good authorities for all these methods,[12-1] and they may all be correct, for there is no evidence that any fixed rule had been laid down in this respect.
Immense masses of such documents were stored in the imperial archives of ancient Mexico.

Torquemada asserts that five cities alone yielded to the Spanish governor on one requisition no less than sixteen thousand volumes or scrolls! Every leaf was destroyed.

Indeed, so thorough and wholesale was the destruction of these memorials now so precious in our eyes that hardly enough remain to whet the wits of antiquaries.