94 



DR SUTHERLAND SIMPSON AND DR J. J. GALBRAITH ON 



The mean temperature in every case is higher than in Period IV., but the mean 

 range is less. The maximum is always reached in the afternoon and the minimum, 

 with one exception (D), in the forenoon ; this shows that both during Periods IV. and 

 V. there was a tendency for the monkeys to fall back into the normal (Period I.) routine, 

 although the incidence of light and darkness did not act as a signal for activity and 

 rest. In fig. 14, the crossed line represents the mean compounded curve for all the 

 monkeys on the last day of Period IV. , the interrupted line the same on the last day of 

 Period V., and the continuous line that on the last day of the normal Period I. It is 

 evident here that the curve obtained at the end of Period V. corresponds much more 

 closely to the normal curve than does that taken at the beginning of Period IV. This 

 would appear to point to the fact that when left to themselves without any guidance 

 from the outside the monkeys tend to adopt the normal rhythm. The curve at the end 

 of Period V. differs from the normal in its diminished amplitude (excluding the last 

 figure 38 "9) and in its regularity. 



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Fig. 14. — Compounded curves from all the monkeys for last day of normal period (I.) 

 (continuous line), last day of Period IV. (crossed line), and last day of Period V. 

 (interrupted line). 



The range for the whole period was for B 2*5° (36'9 at 3 p.m. on 7th to 39*4 at 

 7 p.m. on 6th), for C 2'5° (36"8 at 1 p.m. on 8th to 39*3 at 5 p.m. on 6th), for D 2.5° 

 (36*3 at 9 p.m. on 8th to 38-8 at 3 p.m. on 6th), for E 2-2° (367 at 9 p.m. on lst^to 

 38-9 at 3 p.m. on 4th), for F 2"5° (36'8 at 3 p.m. on 7th to 39"3 at 7 p.m. on 4th), and 

 for the mean of all the monkeys 1'5° (37'4 at 9 a.m. on 8th to 38*9 at 11 p.m. on 7th). 

 Towards the end of this period the monkeys became very irritable and ill-tempered. 



