100 SECTIONAL ADDRESSES. 



encroach. But if the attack was made with sufficiently powerful 

 forces, the centralisation became a menace. An attacking foe able to 

 destroy or damage seriously the irrigation system could cut off at its 

 source the basis of prosperity, and render reconstruction on the old 

 scale almost impossible. In other words, the community became 

 adapted to artificial conditions created by itself; if and when those 

 conditions were destroyed, the survival of the old culture became 

 impossible. 



Turn next to the Mediterranean region, that is to the area in which 

 the typical Mediterranean climate prevails. In so far as the native 

 plants are concerned, this area shows certain broad general resemblances 

 to the river valleys, with some striking differences. Thus the 

 characteristic plant formation is alternately open and closed ; closed 

 during the cooler season of tlie year when the winter rains cause a 

 brief but intense growth of annuals and bulbous or tuberous plants, 

 open during the drought of summer when the trees and shrubs stand 

 apart from each other with bare earth lietween. But the contrast is 

 due, as indicated, to the rainfall conditions, not to flooding. There 

 is thus no natural renewal of fertility, and plants which require much 

 water can only thrive in the cooler season, so that gi'owth is less 

 intense than in either the Nile or the Euphrates-Tigris vallej". 



On the other hand, because of the climatic conditions, trees and 

 shrubs, alike as regards individuals and species, are far more 

 numerously represented in the Mediterranean region. Here, however, 

 we come to a very curious fact, which, though it is familiar enough, 

 does not seem to have been considered in all its bearings. This is that, 

 despite the (relative) wealth of native species of shrubs and trees, those 

 which are cultivated seem to have been for the most part introduced. 

 This is apparently true even of the supremely important olive. The 

 tree occurs in the fossil state, and the olivaster of the maquis is believed 

 by many to be truly wild, not feral. Yet it would appear almost 

 certain that the cultivated olive was introduced, into Europe at least. 

 The same thing is true of great numbers of other species, and of all 

 the fruit-bearing trees now grown in the area there are few indeed 

 which can be reasonably' regarded as having originated there as culti- 

 vated forms. Now, the deduction that I would ckaw is that the 

 Mediterranean area is one in which lessons first learnt elsewhere could 

 be easily practised, but one rendered nnsuited by the natural conditions 

 for the taking of the fii'st steps. Putting the point in another way, 

 I would suggest that when we see, in any part of the area, olives or 

 fig-trees rising from above a plot of wheat or barley, we haA^e to say 

 to ourselves that this is an adaptation to a new set of conditions of 

 the type of cultivation first practised on any scale in Babylonia or 

 Egypt, olive or fig representing date palm and the accompanying trees, 

 the narrow plot of corn the local modification of the broad fertile fields 

 of the river valleys. 



Man was doubtless first attracted to the area, as in the case of the 

 river- valleys, by the natural resources, small though these must have 

 been, even with the addition of the sea fisheries. He became fixed 

 to it when he learnt that the hill-spurs gave safe sites for settlements, 

 while affording easy access to the slopes on which his special form of 



