132 THE DOWNFALL OF THE DERVISHES The native servants, to save themselves trouble or a slight wetting, invariably filled their buckets from the water close to the bank. Anyone who is acquainted with Oriental habits can realise the peril of drinking such water as this, fouled as it was by hundreds of horses, mules, and camels, and taken from a river which is treated as a vast sewer by all the inhabitants along its banks.

The water question was, indeed, a big one throughout the campaign. Some filtered the muddy water as it was, but the process was a very tedious one, for the Birkfeld filter became choked with mud after about a pint of water had passed through it, and then all its internal arrangements had to be cleaned. The native servants were so stupid at any work of this sort, that one generally had to do one’s filtering for oneself; and the exercise was so vigorous that, by the time one had filtered a pint, one was thirsty enough to drink a quart. Another method was to precipitate the mud to some extent by a few grdins of alum; but there are hygienic reasons against the employment of this astringent in drinking water. The safest plan is to let the mud settle, and then boil the water. Yet, even if the water is boiled, one