But although the spirit that collectively animates a group of men cannot be calculated by taking an arithmetical sum, it does depend on that possessed by each individual in the group, and more particularly on what is common to them all and on the nature of the bonds that connect them.  Even a chance group of persons previously unconnected and unrelated is bound together by feelings common to all humanity and may be appealed to collectively on such grounds.  The haphazard street crowd thrills with horror at the sight of a baby toddling in front of a trolley-car and shouts with joy when the motorman stops just in time.  But the same crowd, if composed of newly-arrived Poles, Hungarians and Slovaks, would fail utterly to respond to some patriotic appeal that might move an American crowd profoundly.  You may sway a Methodist congregation with a tale of John Wesley that would leave Presbyterians or Episcopalians cold.  Try a Yale mob with “Boola” and then play the same tune at Princeton, and watch the effect.

Thus, the more carefully our group is selected the more particular and definite are the motives that we can bring to bear in it, and the more powerful will its activities be along its own special lines.  The mob in the street may be roused by working on elemental passions—­so roused it will kill or burn, but you cannot excite in it enthusiasm for Dante’s Inferno, or induce it to contribute money or labor toward the preparation of a new annotated edition.  To get such enthusiasm and stimulate such action you must work upon a body of men selected and brought together for this very purpose.

Besides this, we must draw a distinction between natural and artificial groups.  The group brought together by natural causes and not by man’s contriving is generally lower in the scale of civilization when it acts collectively than any one of its components.  This is the case with a mob, a tribe, even a municipal group.  But an artificial or selected group, where the grouping is for a purpose and has been specially effected with that end in view may act more intelligently, and be, so far as its special activities are concerned, more advanced in the scale of progress than its components as individuals.  There is the same difference as between a man’s hand and a delicate tool.  The former is the result of physical evolution only; the latter of evolution into which the brain of man has entered as a factor.  The tool is not as good for “all round” use as the hand; but to accomplish its particular object it is immeasurably superior.

If, then, we are to accomplish anything by taking advantage of the very peculiar crowd or group psychology—­owing to which a collected body of men may feel as a group and act as a group, differently from the way in which any one of its components would feel or act—­we must see that our group is properly selected and constituted.  This does not mean that we are to go about and choose individuals, one by one, by the exercise of personal