THE TEMPERATURE OF THE MONKEY AND ITS DIURNAL VARIATION. 87 



In B the minimal temperature in this mean curve is found at 7 p.m., in C at 3 

 p.m., in D at 3 p.m., in E at 1 p.m, in F at 7 p.m., and in the average curve obtained 

 from all five at 3 p.m. The maximal was reached in B at 3 a.m. and 7 a.m. (two 

 maxima), in C at 7 a.m., in D at 7 a.m., in E at 1 a.m. and 3 a.m. (two maxima), in F 

 at 3 a.m., and in the mean of all five at 7 a.m. There is thus a greater variation in 

 the time at which the maximal and minimal points are reached than in the normal 

 period. In B the mean range was 1*35° (37*25 to 38*6), in C 1'51° (37*3 to 38-81), in 

 D 1-66° (36-54 to 38-20), in E 1-37° (37*24 to 38-61), in F 1-05° (37*09 to 38*14), and 

 for the average of all five r27° (37"19 to 38*46). In B the range for the whole period 

 was 2'4° (36 - 8 at 9 p.m. April 18th to 39 - 2 at 3 a.m. on 17th and at 7 a.m. on 19th), in 

 C 2*6° (36-7 at 9 p.m. April 13th to 39"3 at 7 a.m. April 19th), in D 3-1° (357 at 1 

 p.m. April 20th to 38'8 at 9 a.m. April 17th), in E 2'3° (36"8 at 5 p.m. on 16th to 

 39*1 at 7 a.m. on 15th and 19th), in F 2-6° (36-1 at 9 a.m. on 13th to 38*7 at 7 a.m. 

 on 15th), and in the mean of all five 1*8° (37'0 on six occasions to 38*8 at 7 a.m. on 

 19th). The greatest range in any single day of twenty-four hours was in B 2*4° (36*8 

 at 9 p.m. on 18th to 39*2 at 7 a.m. on 19th), in C 2*4° (36-7 at 9 p.m. on 14th to 39*1 

 at 7 a.m. on 15th), in D 2-9° (357 at 3 p.m. on 14th to 38*6 at 1 a.m. on 15th), in E 

 2-2° (36-9 at 3 p.m. to 39*1 at 7 a.m. on 15th), in F 2*5° (36*1 at 9 a.m. on 13th to 

 38*6 at 3 a.m. on 14th), and in the average of all five 1-8° (37 '0 at 9 p.m. on 18th to 

 38-8 at 7 a.m. on 19th). 



PERIOD III. 



Extended from 5 p.m. on April 20th till 3 a.m. on April 26th. It was a slight 

 modification of the conditions obtaining in Period II. The monkeys were now tied up 

 and the room darkened at 3 a.m., and liberated at 3 p.m., when daylight was admitted ; 

 the resting and active periods were therefore 3 a.m. to 3 p.m. and 3 p.m. to 3 a.m. 

 respectively. They were fed at midnight and at 3 p.m. The curves gradually 

 assumed a swing corresponding to the changed conditions. See figs. 1-6, pp. 86-88 

 (crossed line), and chart I. In the chart the gradual retardation of the maxima and 

 minima is evident in the case of each of the three (B, C, D) whose curves are 

 represented. In this period the mean minimal temperature was recorded in B at 

 1 p.m., in C at 11 a.m., in D at 1 p.m., in E at 11 a.m., in F at 1 p.m. and 3 p.m., 

 and in the compounded curve from all five at 1 p.m. The maximum in B was reached 

 at 3 a.m., in C at 3 a.m., in D at 1 a.m., in E at 3 a.m., in F at 1 a.m., and in the 

 compounded curve at 3 a.m. The swing during this period was more regular than in 

 Period II., especially in the early part of the latter, as is revealed by the fact that there 

 are fewer secondary curves thrown in on the primary curve. A glance at figs. 1-6, 

 pp. 86-88, will show that of the three mean curves that of Period II. (interrupted line), 

 is the most irregular and contains the greatest number of secondary waves. In B the 

 mean range was 1*93° (36'83 to 3876), in C 1-95° (37-05 to 39*00), in D 2*18° (36*47 



