ns as the _Catholic Encyclopedia_ and Hastings'
_Encyclopedia of Religion and Ethics_. The opening chapters in Marett's
little book on _Anthropology_ are so sanely and admirably written that
they also clear away many prejudices and fears.

With such a concrete body of facts contrasting primitive with modern
civilized social life the student will naturally inquire, How did
these changes come about? At this point should come normally the
answer in terms of what practically all sociologists agree upon;
namely, the three great sets of determining forces or phenomena, the
three "controls": (1) the physical environment (climate, topography,
natural resources, etc.); (2) man's own nature (psycho-physical
factors, the factors in biological evolution, the role of instinct,
race, and possibly the concrete problems of immigration and eugenics);
(3) social heredity (folk-ways, customs, institutions, the arts of
life, the methods of getting a living, significance of tools,
distribution of wealth, standards of living, etc.) A blackboard
diagram will show how these various factors converge upon any given
individual.[37]

The amplification of these three points will ordinarily make up the
body of an introductory course so far as class work goes. Ethnography
should furnish rich illustrative material. But to make class
discussions really productive the student's knowledge of his own
community must be drawn upon. And the best way of getting this
correlation is through community surveys. The student should be
required as parallel laboratory work to prepare a series of chapters
on his ward or part of his ward or village, covering the three sets of
determining factors. The instructor may furnish an outline of the
topics to be investigated, or he may pass around copies of such brief
survey outlines as Aronovici's _Knowing One's Own Community_ or Miss
Byington's _What Social Workers Should Know about Their Own
Communities_; he may also refer them to any one of the rapidly growing
number of good urban and rural surveys as models. But he should not
give too much information as to where materials for student reports
may be obtained. The disciplinary value of having to hunt out facts
and uncover sources is second only to the value of accurate
observation and effective presentation. If the aim of a sociology
course is social efficiency, experience shows no better way of getting
a vivid, sober, first-hand knowledge of community conditions. And
th