VIl] THE FUNCTIONS OF THE SKIN 93 



food raises it. Cold is least well stood by small lean animals, 

 since in them the surface of the bodj' is greater relative to their 

 weight than in larger animals. 



The rise of temperature which occurs during fevers is due 

 partly to a defective dissipation of heat, the regulating mechanisms 

 of the skin being deranged. Thus the skin surface is unusually 

 drj' and hot.* Nevertheless, there is frequently also a great 

 increase in the amount of heat actually produced during fevers, 

 since the quantity dissipated may largely exceed the normal. 



Cold perspiration is a pathological phenomenon and is 

 apparently due to derangement of the nerves supplj'ing the 

 glands. It is unaccompanied by dilatation of the vessels. Dis- 

 ordered sweating is often associated with nervous affections. 



