DIET, AND POWERS OF ABSTINENCE. 83 



even more days of entire privation ; but long 

 abstinence from food is seldom necessary, be- 

 cause, although there are well-attested instances 

 of the existence of tracts of desert frequently 

 crossed by caravans, six days' journey in width, 

 and absolutely without a particle of vegetation,^ 

 yet there are few portions of the Libyan or 

 Arabian deserts where more or less of the shrubs 

 on which the camel feeds do not occur at very 

 much shorter intervals.^ 



1 Denham and Clapperton, i. c. 3. 



2 Nothing can be more erroneous than the popular im- 

 pression with regard to the absolute sterility of the desert. 

 As a general rule, it may be stated that no extensive tracts 

 are wholly devoid of winter vegetation except in rainless 

 regions, which are by no means numerous, and which are 

 themselves often interspersed with oases watered by wells, or 

 springs derived from distant and unknown s«)urces. There 

 are few parts of the Libyan desert where water may not be 

 found at moderate depths, and though Shaw, Travels^ 135, 

 speaks of wells in Wady Reagh one hundred and even two 

 hundred fathoms in depth, yet, in general, water is obtained 

 very near the surface. Wherever there are winter rains, 

 heavy dews in summer, or abundant wells, there is vegetation, 

 arborescent or herbaceous, according to the character of the 

 soil and the supply of moisture ; and even in the drought of 

 summer, the twigs, seed-vessels, and withered foliage of the 

 desert plants supply the frugal camel with the necessary 

 nutriment. The Syrian desert, as it is called, between the 

 Hauran and the Euphrates, is in general carpeted with a 

 luxuriant winter vegetation, and though now laid waste by 



