filed with people by the natural growth of population or by immigration from elsewhere, what is the mode of escape? Neighboring valleys and oases are often themselves filled up, and the horizon of a humble farmer or shepherd rarely includes the distant and strange places that are the centers of industry, where population can be absorbed in increasing numbers. In such a small isolated world what changes of social structure are brought about by the pressure of population? These little des- ert communities are to a large degree self-governing. To what extent have they adapted their home-made regulations to meet the trials of the years of drought? When the rains fail and the cattle die and trade becomes dislocated and feeble, how is the social and business structure maintained ?
It is natural to look to war as a relief from the pressure of population, But, as a matter of fact, war offers very little re- lief from such pressure. The feuds and raids that exist among many desert folk involve a certain percentage of loss by vio- lent death. Hard conditions of life themselves tend to hold the population down by limiting the birth rate in one way or another. Great changes of climate may bring about a general movement of population, and we have scen this illustrated by the sharp droughts of the past few years in the Samara region north and northwest of the Caspian Sea, when hordes of Russians moved west and north into the more favored sections in their search for food. But while such a driving forth of a desert people may have been brought about, I think the effect of it upon history and the social structure has been altogether exaggerated, perhaps largely because it is a picturesque and violent proceeding that appeals to the imagination.
But a picturesque event is oftentimes utterly trivial in its effect upon the character of a people and its modes of gaining a livelihood. If history is a record of picturesque incidents, then the driving forth of a desert people by increasing drought is an important fact. If, on the other hand, history is a record of the growth of culture and ideas, then a given migration from a drought-stricken desert may have very little significance. The fact that a people has gone forth is in itself not to be taken as establishing the importance of the event. Hf it goes steadily
