ents. We have
excellent experimental investigations concerning the influence of the
loss of sleep on intellectual labor and on simple psychomotor
activities. But it would be rather arbitrary to deduce from the
results of those researches anything as to the effect of reduction of
sleep on special economic occupations. Yet such knowledge would be of
high importance. We have in the literature concerned with accidents in
transportation numerous popular discussions about the destructive
influence of loss of sleep on the attention of the locomotive engineer
or of the helmsman or of the chauffeur, but an analysis of the
particular psychophysical processes does not as yet exist and can be
expected only from systematic experiments. Nor has the influence of
hunger on psychotechnical activities been studied in a satisfactory
way.

A number of psychological investigations have been devoted to the
study of the influence of alcohol on various psychical functions and
in this field at least the strictly economic problem of industrial
labor has sometimes been touched. We have the much quoted and much
misinterpreted experiments [45] which were carried on in Germany with
typesetters. The workmen received definite quantities of heavy wine at
a particular point in the work and the number of letters which they
were able to set during the following quarter-hours were measured and
compared with their normal achievement in fifteen minutes. The
reduction of efficiency amounted on the average to 15 per cent of the
output. It may be mentioned that the loss referred only to the
quantity of the work and not at all to the quality. The well-known
subjective illusory feeling of the subjects was not lacking; they
themselves believed that the wine had reinforced their working power.
As soon as such experiments are put into the service of economic life,
they will have to be carried on with much more accurate adjustment to
the special conditions, with subtler gradation of the stimuli, and
especially with careful study of individual factors. But at first it
seems more in the interest of the practical task that the extremely
complicated problem of the influence of alcohol be followed up by
purely theoretical research in the laboratory in order that the effect
may be resolved into its various components. We must first find the
exact facts concerning the influence of alcohol on elementary
processes of mental life, such as perception, attention, memory, and
s