sk. Moreover, where not merely
such mental defects, but more subtly shaded variations within normal
limits are involved, it would be superficial, if only the mental
states were examined and not at the same time the mental requirements
of the vocations themselves. The vocation should rather remain the
starting-point. We must at first find out what demands on the mental
system are made by it and we must grade these demands in order to
recognize the more or less important ones, and, especially for the
important ones, we must then seek exact standards with experimental
methods.

Such an experimental investigation may proceed according to either of
two different principles. One way is to take the mental process which
is demanded by the industrial work as an undivided whole. In this case
we have to construct experimental conditions under which this total
activity can be performed in a gradual, measurable way. The psychical
part of the vocational work thus becomes schematized, and is simply
rendered experimentally on a reduced scale. The other way is to
resolve the mental process into its components and to test every
single elementary function in its isolated form. In this latter case
the examination has the advantage of having at its disposal all the
familiar methods of experimental psychology, while in the first case
for every special vocational situation perfectly new experimental
tests must be devised.

Whether the one or the other method is to be preferred must depend
upon the nature of the particular commercial or industrial calling,
and accordingly presupposes a careful analysis of the special
economical processes. It is, indeed, easy to recognize that in certain
industrial activities a series of psychical functions is in question
which all lie side by side and which do not fuse into one united
total process, however much they may influence one another. But for
many industrial tasks just this unity is the essential condition. The
testing of the mental elements would be in such cases as insufficient
as if we were to test a machine with reference to its parts only and
not with reference to its total united performance. Even in this
latter case this unified function does not represent the total
personality: it is always merely a segment of the whole mental life.
We may examine with psychological methods, for instance, the fitness
of an employee for a technical vocation and may test the particular
complex unified combina