The fixed population of Mecca in 1878 was estimated by Assistant-Surgeon 'Abd el-Razzaq at 50,000 to 60,000; there is a large floating population--and that not merely at the proper season of pilgrimage, the pilgrims of one season often beginning to arrive before those of the former season have all dispersed. At the height of the season the town is much overcrowded, and the entire want of a drainage system is severely felt. Fortunately good water is tolerably plentiful; for, though the wells are mostly undrinkable, and even the famous Zamzam water only available for medicinal or religious purposes, the underground conduit from beyond Arafa, completed by Sultan Selim II. in 1571, supplies to the public fountains a sweet and light water, containing, according to 'Abd el-Razzaq, a large amount of chlorides. The water is said to be free to townsmen, but is sold to the pilgrims at a rather high rate.[11] Medieval writers celebrate the copious supplies, especially of fine fruits, brought to the city from Taif and other fertile parts of Arabia. These fruits are still famous; rice and other foreign products are brought by sea to Jidda; mutton, milk and butter are plentifully supplied from the desert.[12] The industries all centre in the pilgrimage; the chief object of every Meccan--from the notables and sheikhs, who use their influence to gain custom for the Jidda speculators in the pilgrim traffic, down to the cicerones, pilgrim brokers, lodging-house keepers, and mendicants at the holy places--being to pillage the visitor in every possible way. The fanaticism of the Meccan is an affair of the purse; the mongrel population (for the town is by no means purely Arab) has exchanged the virtues of the Bedouin for the worst corruptions of Eastern town life, without casting off the ferocity of the desert, and it is hardly possible to find a worse certificate of character than the three parallel gashes on each cheek, called Tashrit, which are the customary mark of birth in the holy city. The unspeakable vices of Mecca are a scandal to all Islam, and a constant source of wonder to pious pilgrims.[13] The slave trade has connexions with the pilgrimage which are not thoroughly clear; but under cover of the pilgrimage a great deal of importation and exportation of slaves goes on.