Dermatoses Due To Physical Causes

THE BODY requires a certain amount of heat, but beyond definite limits, insufficient or excessive amounts are injurious. The local action of excessive heat causes burns or scalds, and on the other hand, undue cold causes chilblains, frostbite, and congelation. Thresholds of tolerance exist in all body structures sensitive to electromagnetic vibrations of other frequencies such as x-rays, radium rays, and ultraviolet rays. The eye, which is sensitive to vibrations within the component of the spectrum known as visible light, is an example of a special sense organ which has similar limits. The skin, which is exposed to so many external physical forces, is more subject to injuries caused by them than any other organ.