. Were it not for this particular feature of the method,
the number of choices recorded after June 17 would unquestionably be
very much greater than the table indicates.

The new method proved a severe test of the orang utan's patience and
perseverance, for he had to work much harder than formerly for his
reward, and often became much fatigued before completing the regular
series of ten trials. Early in the use of this method, he developed the
habit of rolling around from exit door to starting point by a series of
somersaults. When especially discouraged he would often bump his head
against the floor so hard that I could hear the dull thud. As has been
noted, I found it desirable to vary the procedure repeatedly. It proved
especially interesting to give one series per day with the round trip as
punishment and another series with confinement as punishment.

Day after day, as the experiment progressed, slight or great
fluctuations of the ratios of right to wrong choices appeared, but
without consistent improvement. There was, to be sure, as the last
column of table 9 shows, a radical improvement during the first six
hundred and fifty trials, for the number of right choices per series
increased from 0 to 8. But, as the observations were continued from day
to day, it became more and more evident that the animal was merely
passing from tendency to tendency--method to method--mixing tendencies,
and occasionally developing new ones, without approach to the solution
of the problem. This fact would have led me to discontinue the work much
earlier than I actually did had it not been for the peculiarity of the
results obtained with problem 1. It seemed not improbable that at any
time Julius might succeed in perfectly solving this problem over night
precisely as he had solved the first problem.

A curiously interesting bit of behavior appeared for the first time on
June 29. Julius had gone to the first box at the right end of the group,
and instead of entering, he had wheeled around toward his right, and
turning a complete circle, faced the right box, which he promptly
entered. Subsequently, the tendency developed and the method was used
with increasing frequency. On June 30, it appeared in the first series,
four times, in the second series, six times; on July 1, in the first
series, three times, and in the second series, four times; on July 2, in
the first series, five times, and in the second series, nine times. It
was indeed o