THE SKIN. 223 



able to resist it, and in some instances their health failed, 

 and they sank under the experiment. 



536. More clothing is necessary in infancy and in old 

 age, when the generation of internal heat is more feeble than 

 in the middle periods of active life. It is a mistake to sup- 

 pose that infants should be lightly clothed, or that the neces- 

 sity of warm garments for them is the mere creation of habit. 

 They can give out no more heat than is prepared within ; and 

 as this is less in them than in others, they cannot bear an 

 equal loss without reducing their temperature below the 

 natural standard. They must therefore be protected with 

 more caution. The same law applies to the aged, and even 

 more strictly, inasmuch as their sensations are so blunted 

 that they cannot so easily tell when they are cold. And 

 oftentimes they are suffering serious disturbance before 

 they are aware of it. 



537. It must not be inferred, from the preceding sections, 

 that men who are engaged in sedentary employments, or who 

 are otherwise than robust, cannot, by discreet exposure, ac- 

 quire a power to endure the weather of cold seasons. Pre- 

 cisely the reverse is the fact. But this exposure must be 

 just in proportion to the power of the body to bear it, and 

 increased only as fast as the energies of the constitution 

 increase. It should always be accompanied with so much 

 clothing that the body shall not suffer while abroad, and the 

 chill must not be so great that reaction will not take place 

 immediately after returning to the house. With these pre- 

 cautions of suiting the exposure to the powers of the consti- 

 tution, wearing clothing sufficient for comfort, or exercising 

 actively enough to sustain the increased demands for heat, 

 even the feeble can generally acquire a power to endure 

 all the weather of this climate. 



