That my mules might be in condition for the hard travel before me, it was necessary to have them shod: a precaution, however, which is seldom used in the north of Mexico, either [Pg170] with mules or horses. Owing a little to the peculiar breed, but more still no doubt to the dryness of the climate, Mexican animals have unusually hard hoofs. Many will travel for weeks, and even months, over the firm[121] and often rocky roads of the interior (the pack-mules carrying their huge loads), without any protection whatever to the feet, save that which nature has provided. But most of mine being a little tender-footed, I engaged Mexican _herreros_ to fit them out in their own peculiar style. Like almost everything else of their manufacturing, their mule-shoes are of a rather primitive model--broad thin plates, tacked on with large club-headed nails. But the expertness of the shoers compensated in some degree for the defects of the _herraduras_. It made but little odds how wild and vicious the mule--an assistant would draw up his foot in an instant, and soon place him _hors de combat_; and then fixing a nail, the shoer {95} would drive it to the head at a single stroke, standing usually at full arm's length, while the assistant held the foot. Thus in less than half the time I had ever witnessed the execution of a similar job before, they had completely shod more than twenty of the most unruly brutes--without once resorting to the expedient so usual in such cases, of throwing the animals upon the ground. Just as the process of shoeing my mules had been completed, a person who proved to be a public officer entered the _corral_, and pointing to the mules, very politely informed me that they were wanted by the government to transport troops to Zacatecas. "They will be called for to-morrow afternoon," he continued; "let them not be removed!" I had of course to bow acquiescence to this imperative edict, well knowing that all remonstrance would be vain; yet fully [Pg171] determined to be a considerable distance on the road northward before that 'morrow' should be very far advanced. But a new difficulty now presented itself. I must procure a _guia_ or passport for my cargo of merchandise, with a _responsible endorser_,--an additional imposition I was wholly unprepared for, as I was then ignorant of any law to that effect being in force, and had not a single acquaintance in the city. I was utterly at a loss what to do: under any other circumstances I might have left the amount of the _derecho de consumo_ in deposit, as others have been obliged to do on similar occasions; but {96} unfortunately I had laid out the last dollar of my available means.