DAILY ROUTINE AND BODY TEMPERATURE. 235 
and involuntarily one tries to avoid all such things; the movements become gliding and 
noiseless, resembling those of other night animals, and are much less definite than in 
the day-time. A round in the night will therefore fail to raise the temperature like a 
corresponding walk in the day-time. And one is never sitting so still as in the 
mienb; .. . 
The psychical factor might naturally be expected to have a greater influence on the 
human subject than on the lower animals, and this may account for the fact that in the 
monkey the body-temperature curve can be reversed by reversing the daily routine 
(Stmpson and GatpraitH™). Here, however, the case is somewhat different in another 
respect, since the reversed conditions were imposed on a colony of monkeys instead of 
an isolated individual. 
Instead of experimenting on a single individual, then, the proper method would be 
to apply the ‘“‘ reversed” routine to the whole society in which the individual lives, but 
this is inconsistent with social life in civilised communities. Such an experiment, how- 
ever, may be carried out on a high-arctic expedition during the long polar night or day, 
and this LinpHarp did on the members of the party. For this he preferred the winter 
night to the perpetual day of summer, since the “sun occasions a continual unrest, the 
working hours are unlimited, and a little food emancipates one from the regular meals. 
It will therefore be very difticult for all to adopt the same mode of life, .. . . Apart 
from this, the difference in the intensity of the light is much more pronounced in 
summer than in winter, just as the variations in the day-and-night temperature are 
much greater. During the polar night the case is different. All lamps are put out at 
certain fixed hours appointed by the leader of the expedition ; then it is night: during 
the remaining hours the lamps are lit and we have day. As practically all work is done 
indoors, the dining hours are kept by everyone; and in the open air the light by day 
and at night does not vary appreciably, and the changes in temperature are com- 
paratively small.” 
This experiment was carried out in January 1907, in lat. 76° 46’ N., on the whole 
ship’s crew. The transition was made very quickly and easily. Bedtime was delayed 
once four hours, and then eight hours by the insertion of an extra meal, and so in two 
days the “reversal” was accomplished. The lamp was lit and extinguished at a fixed 
time as before, but twelve hours later, and all met at the table as usual at the 
“reversed” meal hours. Only on clear days at “noon” a little brightness in the 
southern sky might be missed, otherwise the change was betrayed by no external sign. 
‘All were conscious of the fact that this change had been made, but in the great 
majority this did not give rise to a feeling of anything unusual. “Time rolled along 
on its even, ordinary way. More than half of the twenty-eight members of the 
expedition felt, indeed, just as usual as soon as the transition had been accomplished ; 
after five to six days only a few were a little indisposed to work, sleeping less well in 
the “night” and becoming sleepy at various times of the “day.” The function altered 
* Simpson and GatpraitH, Trans. Roy. Soc. Hdin., vol. xlv., part 1., 1905, p. 65. 
