90 



DR SUTHERLAND SIMPSON AND DE J. J. GALBRAITH ON 



minutes every two hours occupied in taking the temperatures, when a single small 

 electric lamp was used. They were fed at 9 a.m. and 6 p.m., but were otherwise left 

 absolutely free, with no guide as to what routine they should adopt. 

















A. 



M. 









Noon 









p. 



M. 















39° 



















































8 



,A 



> 





> 

























y 



y 



t 











J^ - 



6 

 4 

 2 







ii 



\ 





















t 



/ 



/ 



* 







if. 



/ 

 / 



V^" 



^ 







































/ 

 / 





















\ 









































38° 









» V 



























/ 

















































i 

















8 

 6 











\n( 

























ij. 

























\ 

 \ 

















































i 



%-- 



-< 



Kj 















■ ■■-, t 



1 

 it 



















4 































s 











































\ 



Y* 



























O-o 





















































12 1234567 



9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 Hours 



Fig. 7. — Compounded curves from all five monkeys for last day of normal period 

 (continuous line), first day of Period II. (crossed line), and last day of 

 Period III (interrupted line). 



The swing was carried forward from Period III., and is evident for the first few 

 days in the plotted curves in chart I., but towards the end of this period it became 

 very irregular, no two monkeys apparently observing the same routine of rest and 

 activity. The most notable points are given in the following table : — 



PERIOD IV. — Continuous Darkness for Seven Days. 



B 



C 



I) 

 E 

 F 

 Average 



Mean 



Mean 



Temperature. 



Range. 



38'25 



1 13 



37-97 



0-99 



37-40 



66 



38-04 



113 



37-88 



0-94 



37 91 



0-73 



Minimum. 



37-52 at 5 a.m. 



37-43 

 36-97 



37-47 

 37-48 

 37-47 



5 „ 

 9 p.m. 

 5 a.m. 

 5 „ 

 5 ,. 



Maximum. 



65 at 

 4 „ 

 63 ,, 

 60 ,, 

 42 ,, 

 20 ,, 



9 p.m. 



1 „ 



5 and 9 a.m. 



9 a.m. 

 11 ,, 

 11 ,, 



On comparing this table with that of the normal Period L, it will be found that 

 the mean temperature is in every case diminished, that the range is much diminished, 

 and that with one exception (D) it has returned to the type characteristic of the 

 normal Period I. — lowest in the morning and early forenoon, highest in the afternoon 

 [see figs. 8 to 13, in which the mean curves of Periods IV. (interrupted line) and V. 

 (crossed line) are contrasted with those of Period I. (continuous line)]. 



I 



