200 GRAND STRATEGY OF EVOLUTION 



tion. If readjustments in the ways and means of con- 

 veyance are rightly made to meet these new conditions, 

 growth may safely continue indefinitely; if not, it will 

 be automatically checked by unbalanced, or inequi- 

 table exchange, or something may "yield of itself," or 

 break, or some more general catastrophe may occur. 



A village, for example, may grow in length along 

 both sides of a common road, in single storied houses. 

 Or, as the population increases, it may expand right 

 and left, by the more or less regular addition of suc- 

 cessive cross streets with their supplementary lines and 

 channels of conveyance; or up and down, by the suc- 

 cessive additions of deeper cellars and successive stories. 

 The relative rate and direction of growth will thus de- 

 termine the shape and structure of the city as a whole, 

 and the distribution of its chief lines of conveyance; or 

 it will determine, as we say, the architectural plan of 

 the city and the way in which its vital services respond 

 to the demands of growth. 



But the older the city, and the more firmly its 

 method of growth is established, let us say along radial, 

 parallel, zigzag, or vertical lines, or if built of stone 

 in place of wood, the more difficult or dangerous it will 

 be to make radical changes in it. Although the more 

 imperative readjustments and improvements may be 

 made at subsequent periods, the original materials and 

 methods of growth, and the location of its great civic 

 centres will long remain, affecting the economy of its 

 life in varying degrees; a permanent check, or an invi- 

 tation to further growth; a serious handicap, or a po- 

 tential source of profit, as the case may be. 



So it is with the growth of all living organisms. 



