of the psychophysical system sets
in with every act of attention and reaches its climax in sleep, which
surely does no harm to the mind. It may be thoroughly advantageous for
the total work of the normal, healthy, average workingman if the after
effects of the motor excitement of the day are eliminated by a mild,
short alcoholic poisoning in the evening. It may produce that
narrowing and dulling of consciousness which extinguishes the cares
and sorrows of the day and secures the night's sleep, and through it
increased efficiency the next morning. Systematic experiments with
exact relation to the various technical demands must slowly bring real
insight into this complex situation. The usual hasty generalization
from a few experiments with alcohol for partisan interests is surely
not justified in the present unsatisfactory state of knowledge.[47]

Perhaps we know still less of the influences which coffee, tea,
tobacco, sweets, and so on exert on the life of the industrial worker.
It will be wise to resolve these stimuli in daily use into their
elements and to study the effects of each element in isolated form. To
know, for instance, the effects of caffein on the psychophysical
activities does not mean to know the effects of tea or coffee, which
contain a variety of other substances besides the caffein, substances
which may be supposed to modify the effect of the caffein. Yet the
first step must in this case be the study of the effects of the
isolated caffein, before the total influences of the familiar
beverages can be followed up. An excellent investigation of this
caffein effect on various psychological and psychomotor functions has
recently been completed.[48] When the caffein effect on tapping
movements was studied, it was found that it works as a stimulation,
sometimes preceded by a slight initial retardation. It persists from
one to two hours after doses of from one to three grains and as long
as four hours after doses of six grains. The steadiness test showed a
slight nervousness after several hours after doses of from one to four
grains. After six grains there is pronounced unsteadiness. A complex
test in cooerdination indicated that the effect of small, amounts of
caffein is a stimulation and that of large amounts a retardation.
Correspondingly the speed of performance in typewriting is heightened
by small doses of caffein and retarded by larger doses. In both cases
the quality of the performance as measured by t