PREFACE 



Circumstances over which I had no control 

 induced me to study the conditions of Ufe in Lower 

 Mesopotamia and in North- West Persia for more 

 than two years. I had previously seen desert life 

 in spring-time during a short visit to Algeria, and 

 more recently I have lived in Jerusalem, a city 

 which is not indeed in the desert, but within easy 

 reach of the deserts of Southern Palestine and of the 

 lower end of the Jordan depression. I have endeav- 

 oured to summarize my own observations and to 

 elucidate their meaning by comparison with what 

 has been observed in other deserts. The desert is an 

 environment unspoilt by the hand of man, so that 

 one can more clearly observe the interaction of 

 plant and animal upon each other, and the depen- 

 dence of the living creatures upon climate and 

 other physical conditions. 



This " oecological " study will, I hope, prove 

 interesting to many who delight in natural history, 

 but who have never had an opportunity to make 

 themselves acquainted with the more formal aspects 

 of Zoology. As every reader will discover, the study 

 of the animal in relation to its surroundings is beset 

 with difficulties ; we are ignorant of certain details 



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