The organization of the city, the character of the urban environment and of the discipline which it imposes is finally determined by the size of the population, its concentration and distribution within the city area. For this reason it is important to study the growth of cities, to compare the idiosyncrasies in the distribution of city populations. Some of the first things we want to know about the city, therefore are:
What are the sources of the city’s population?
What part of its population growth is normal, i.e., due to excess of births over deaths?
What part is due to migration (a) of native stocks? (b) foreign stocks?
What are the outstanding “natural” areas, i.e., areas of population segregation?
How is distribution of population within the city area affected by (a) economic interest, i.e., land values? (b) by sentimental interest, race? vocation, etc.?
Where within the city is the population declining? Where is it expanding?
Where are population growth and the size of families within the different natural areas of the city correlated with births and deaths, with marriages and divorces, with house rents and standards of living?
The neighborhood.—Proximity and neighborly contact are the basis for the simplest and most elementary form of association with which we have to do in the organization of city life. Local interests and associations breed local sentiment, and, under a system which makes residence the basis for participation in the government, the neighborhood becomes the basis of political control. In the social and political organization of the city it is the smallest local unit.
It is surely one of the most remarkable of all social facts that, coming down from untold ages, there should be this instinctive understanding that the man who establishes his home beside yours begins to have a claim upon your sense of comradeship.... The neighborhood is a social unit which, by its clear definition of outline, its inner organic completeness, its hair-trigger reactions, may be fairly considered as functioning like a social mind.... The local boss, however autocratic he may be in the larger sphere of the city with the power he gets from the neighborhood, must always be in and of the people; and he is very careful not to try to deceive the local people so far as their local interests are concerned. It is hard to fool a neighborhood about its own affairs.[[3]]