THE TEMPERATURE OF THE MONKEY AND ITS DIURNAL VARIATION. 77 



considerably in excess of that found in man. At the same time it was evident that the 

 temperature of the monkey was exceedingly susceptible to variations in muscular 

 activity, showing very considerable rises after even short periods of active exercise. 

 Taking these two facts into consideration, we concluded that the temperature control in 

 the monkey was less perfect than in man, inasmuch as, so far as our investigations 

 went, variations in the controlling factors caused relatively greater variations in the 

 body temperature. 



Method of Procedure. 



We therefore decided to attempt an experiment on the monkey similar to that 

 which Mosso (7) and Benedict (G) had made in man. extending over a sufficiently long 

 period and in a sufficient number of animals to make the results conclusive. We took 

 all precautions to obviate fallacy which seemed to us necessary from our previous 

 experience. We se]ected only animals which submitted to the operation without 

 struggling. They were fed at regular intervals and disposed of their food at their 

 leisure. They were kept in a quiet part of the laboratory, in a large room, where they 

 were allowed complete freedom to roam about, and as the most important part of the 

 experiment was made during the Easter vacation, the outside disturbances were reduced 

 to a minimum. The room was artificially heated, and the temperature kept as constant 

 as possible night and day. Variations in the room temperature within these narrow 

 limits (15 to 20° C. for the greater part of the time) were found to have no appreciable 

 influence on the curve of body temperature. Ventilation was good, and all the condi- 

 tions were as favourable as it was possible to make them. 



Before beginning our observations, all the monkeys chosen were tested with Koch's 

 tuberculin, but none of them gave any reaction. One animal, however, was found to 

 have tuberculosis post-mortem, but its temperature after the fourteenth day exhibited 

 marked peculiarities, sufficient of themselves to distinguish it from the curves of the 

 others, and it is not included in the number from which the various curves were 

 obtained. One of our monkeys developed acute phosphorus poisoning from having 

 eaten some lucifer matches, and died within a few hours, but another of the same 

 species was substituted for it. Its temperature readings up till the day on which it 

 ate the poison are included in the averages. Post-mortem examination showed no 

 trace of tuberculous disease. 



The number and description of the animals, not including the one which was found 

 to have tuberculosis, may be briefly given as follows : — 



Monkey A {Macacus rhcesus). £ adult (died of acute phosphorus poisoning). 

 B ,, ,, § ,, (substituted for A). 



C ,, ,, $ immature. 



I) ( ,, cyanomolgus). $ aged. 

 E (Papio hamadryas). $ adult. 

 F (Gercopithecus patas). $ adult. 



