THE PHYSIOLOGICAL EVOLUTION, ETC. 389 



34*9°. This table is introduced chiefly, however, in order to 

 illustrate another point, viz., the effect of the environmental 

 temperature on that of the animal under experiment. We 

 see that with a single exception the body temperature rose 

 regularly, with the rise of external temperature, from 37*0° 

 to 39'5°- This rise is almost as considerable as was observed 

 by Sutherland in the Koala, though not nearly so great as 

 in Echidna, and it goes to prove that in the guineapig, at 

 least, the power of regulation of the body temperature is by 

 no means perfect. 



To return to the experiments on man, Loewy l made 

 numerous observations in which the subject of experiment 

 lay at rest on a sofa, and had his respiratory exchange de- 

 termined when he was in a clothed and unclothed condition. 

 In other experiments warm and cold baths were used. The 

 chief point of these experiments lay in the fact that especial 

 attention was paid to the presence or absence of shivering 

 and other movements of the subject when exposed to cold. 

 It was found that the oxygen intake remained uninfluenced 

 by the exposure to cold in twenty cases, and was diminished 

 in nine of them. It was increased in twenty-six cases, but 

 in thirteen of these shivering and muscular movements were 

 observed, and it was probable that in the other cases there 

 were also some such movements, though not sufficient to be 

 observed. It would therefore seem that on exposure to low 

 temperatures increased movement is the chief if not the only 

 means the nervous system possesses of increasing the heat 

 production of the body. This conclusion has been con- 

 firmed by the numerous experiments recently made by 

 Johansson, 2 as also by the fact that in the various experi- 

 ments which have been made on dogs, guineapigs, rabbits 

 and mice it was always found that the animals were more 

 active and showed increased movements on exposure to 

 lower temperatures. In Johansson's observations, the sub- 

 ject of experiment was seated or lay in bed for a certain 

 time, and the carbonic acid output was determined. All 

 the clothing was then removed, and the carbonic acid out- 



1 /finger's Archiv., Bd. xlvi., S. 189, 1890. 



2 Skandinavische Archiv. f. Physiol., Bd. vii., S. 123, 1896. 



