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Proceedings of the Royal Society of Edinburgh. [Sess. 
normal, hut could do no more. Their energy was such that it could not 
produce definite spurts, hut what energy they had they were able to 
maintain, although at a subnormal level. Even the winding up of the test 
Curve X. — Average Curve of the “Quiescent” Cases. 
Showing percentage variation from minute to minute from the average rate 
of the test. 
no — ... — — no 
95 95 
caused no definite alteration in the output of their work, for the terminal 
spurt was insignificant. 
The curve of the mental work of the patients in the depressed phase 
of the disease (Curve Y) was in its first half markedly different from the 
last two curves. The energy with which the test began was no greater, 
yet the subsequent fall was markedly increased. In the reaction to this 
Curve Y. — Average Curve of the “Depressed” Cases. 
Showing percentage variation from minute to minute from the average rate 
of the test. 
initial lapse and to subsequent lapses, a feature appeared which I am 
inclined to think is characteristic of this mental state. The recovery was 
performed in a series of steps ; thus, the maximum depression of the output 
in the first lapse occurred in the third minute ; in the fourth minute the 
rate increased ; and after a lapse in the fifth minute, in the sixth it reached 
its maximum. During that time the task had apparently become pro- 
gressively easier for the patient ; the patient was able more and more 
thoroughly to concentrate ; his psychomotor inertia was gradually over- 
come and the output tended to increase. But this effort induced a reaction, 
and a gradual falling off occurred, for during the four subsequent minutes, 
from the sixth to the tenth, the output remained below the normal. 
