chemical knowledge is applied to the construction
of anarchistic bombs. But while psychology, as we have emphasized
before, cannot from its own point of view determine the value of the
end, the psychologist as a human being is certainly willing to
cooeperate only where the soundness and correctness of the ends are
evident from the point of view of social welfare.

In order to demonstrate the principle of this kind of psychotechnical
help with fuller detail, at least by one illustration, I may discuss
the case of the advertisements, the more as this problem has already
been taken up in a somewhat systematic way by the psychological
laboratories. We have a number of careful experimental investigations
referring to the memory-value, the attention-value, the
suggestion-value, and other mental effects of the printed business
advertisements. Of course this group of experimental investigations at
once suggests an objection which we cannot ignore. A business
advertisement, as it appears in the newspapers, is such an extremely
trivial thing and so completely devoted to the egotistical desire for
profit that it seems undignified for the scientist to spend his time
on such nothings and to shoot sparrows with his laboratory
cannon-balls. But on the one side nothing can be unworthy of thorough
study from a strictly theoretical point of view. The dirtiest chemical
substance may become of greatest importance for chemistry, and the
ugliest insect for zooelogy. On the other side, if the practical point
of view of the applied sciences is taken, the importance of the
inquiry may stand in direct relation to the intensity of the human
demand which is to be satisfied by the new knowledge. Present-day
society is so organized that the economic advertisement surely serves
a need, and its intensity is expressed by the well-known fact that in
every year billions are paid for advertising. Measured by the amount
of expenditure, advertising has become one of the largest and
economically most important human industries. It is, then, not
astonishing that scientists consider it worth while to examine the
exact foundations of this industry, but it is surprising that this
industry could reach such an enormous development without being guided
by the spirit of scientific exactitude which appears a matter of
course in every other large business. As it is a function of science
to study the physics of incandescent lamps or gas motors so as to
bring the econ