The most common disease of the foot is the _cheggag_, or chaps, which are healed by having grease rubbed in, and by being afterwards cauterised with a hot iron. Sometimes these chaps are so long and deep that they are obliged to be sewed up. The thread used for the purpose is made of camel's sinews dried in the sun, and split into parts as fine as silk; spun camel's hair is, likewise, employed. All the inhabitants of the desert make use of this thread to mend their saddles, and bridles, and wooden platters. Every one carries about with him a housewife, a knife, and a needle. Not a few turn their powers of pedestrianism to a good account, and make it their profession. Hence come the runners and messengers, who gird themselves tightly with a belt. These who are called _rekass_ undertake affairs of great urgency. They will do in four days what the ordinary runners take ten to accomplish. They scarcely ever stop, but if they find it necessary to rest they count sixty inhalations of the breath and start again immediately. A _rekass_ who receives four francs for going sixty leagues thinks himself well paid. This modest reward, however, is the more highly appreciated because it is paid in actual money. Specie is rare, and is the smallest portion of an Arab's fortune. The restricted circulation, and the facility of providing for the principal necessities of life without buying or selling, by simply having occasional recourse to barter are far from lowering the value of coined money. In the desert a special messenger travels night and day, and sleeps only two hours in the twenty-four. When he lies down he fastens to his foot a piece of cord of a certain length, to which he sets fire; and, just as it is nearly burned out, the heat awakens him. In 1846, an Arab, named El-Thouamy, a native of Leghrouât, was sent by the Kalifa Sid-Hamed-ben-Salem to Berryân, a town situated in the country of the Beni-Mzab. Starting at five in the morning from Kuesyr-el-Heyrân, he reached his destination about seven in the evening of the same day. In fourteen hours he had covered 168 kilomètres, travelling at the rate of twelve kilomètres an hour. This same Thouamy set out one day from Negoussa to go to Berryân, a distance of 180 kilomètres, charged with an important message, and accomplished the journey in sixteen hours. During both of these courses this man eat only a few dates and drank about two _litres_ of water.