146 DIAGNOSIS OF THE RAGLE. 



the perspective to which we are accustomed in temperate climates, 

 which are always more or less misty. Objects appear much nearer 

 than they are in reality, because they are more distinctly visible, and 

 also because nothing intervenes between them and the observer. 

 Their dimensions, too, become arbitrary, for want of standards of 

 comparison by which to measure them. So the trees and the moun- 

 tains where the weary traveller hopes to obtain a temporary repose 

 and a passing shelter from the Pythian' s fiery arrows, seem constantly 

 to recede before him, like the rainbow when pursued by the ignorant 

 peasant ; and, until experience has taught him to rectify the apparent 

 testimony of his senses, he is doomed, like Tantalus, to be the victim 

 of continual deceptions, 



" Ev'n in the circling floods refreshment craves. 

 And pines with thirst amidst a sea of waves ; 

 When to the water he his lip applies, 

 Back from his lip the treacherous water flies."* 



Nor is this all ; hunger, thirst, weariness, and especially the 

 action of the solar heat upon the brain, determine a peculiar patho- 

 logical condition, a species of mental intoxication or delirium which 

 powerfully predisposes the victim to hallucinations, and deprives the 

 mind of that self-control which would enable it to chase away the 

 phantoms that haunt it. To this affection, whose symptoms are 

 frequently but erroneously confounded with those of the mirage, the 

 Arabs have given a specific name. They call it Ragle. A distin- 

 guished French traveller has described it with exhaustive fulness, -f- 

 and he attributes it to fatigue, excessive heat, and want of sleep. 



It shows itself most commonly at night, and in dreams, attacks 

 of nightmare, and a somnambulism of which the sufferer is perfectly 

 conscious, without being able to throw it off. By day strange hallu- 

 cinations affect the sight, the hearing, and even, though less power- 

 fully, the senses of taste and smell. The aberration extends, as far 

 as the sight is concerned, to the objects which we are in the habit of 



* Homer, " Odyssey," book xi., Pope's Translation. 



t M. lo Comte d'Escayrac de Lauture, " Le D&ert et le Soudan " (Paris, 1853). 



