9S SECTIONAL ADDRESSES. 



be of a liigiily specialised type, are easily overwhelmed when contact 

 with the outside world does occur, just as island animals tend to 

 disappear before introduced forms. 



Now with these general statements as starting-point, let us consider 

 some facts in regard to the development of civilisation in Europe and 

 the margins of the adjacent continents. 



In this area history has seen three successive great foci of civilisa- 

 tion, each based on well-marked and distinctive geographical conditions. 

 The development of the three types has been successive and not simul- 

 taneous, and there has thus been a steady shift in time of the main 

 focus, a shift westward and north-westward. The three types of 

 human societies alluded to are, of course, (1) the river valley type as 

 represented in Babylonia and early Egypt ; (2) the Mediterranean type 

 on parts of the seaboard of the Midland sea ; (3) the forest type of 

 Europe proper, itself becoming progressively more and more influenced 

 by the greater ocean to the west, so that forest influences have steadily 

 given way to maritime ones. 



We have tO' ask oiurselves, then, what effects the factors already 

 considered have had on the origin, gi-owth, and further development, or 

 decay, of each of these three? In other words, what in each case were 

 the geographical causes which first fixed man to a particular area in 

 which he was able to cultivate useful plants ? What gave the necessary 

 isolation and safety during the early stages? Finally, to what extent 

 were the conditions such as to give that necessary safety without leading 

 to tlie loss of the power of continued adaptive modification, as expressed 

 either in the capacity to spread over adjacent areas showing progressively 

 increasing differences, or in that of responding to changes within the 

 home area? 



In the case of the river-valley areas, as represented in the Tigris- 

 Euphrates region and the Nile valley, and in that of the Mediterranean 

 seaboard, several geographers, among whom Prof. Myres may be 

 especially mentioned, have discussed the conditions favourable to the 

 early development of civilisation. It is therefore not necessary to 

 consider the geography of these areas in detail. But, beginning with 

 Babylonia and Egypt, I should like to put the causes which seem to 

 me to have promoted fixation quite briefly. Among them we must 

 certainly include the primitive natural resources, scanty though these 

 doubtless were. The birds of the valley marshes, the relatively small 

 number of mammals, the fish of the rivers, must have supplied a certain 

 amount of the animal food. The date palm, in the Tigris-Euphrates 

 areas at least, would, even in its wild state, doubtless yield a fruit of 

 some value in the very early days. 



But. as an imnortant factor in the development of cultivation, I 

 would lay especial stress upon the presence of what the botanists 

 call the ' open ' plant formation. Native trees, as we know, are very 

 few, the date tpalm, one of the most characteristic, being strictly 

 limited in distribution by its need for water at the roots. For the 

 greater part of the year the ground between the scattered trees is 

 naturally either devoid of vegetation, or this is represented only by a 

 few desert ])lants. But after tlie periodic flooding by the rivers, an 

 abundant growth of vegetation springs up. The plants may be annuals, 



