MANUAL OF NATURE STUDY. 
77 
Tight shoes will cause corns, which, when once 
formed, are very troublesome. Any rough place in 
the shoe, pressing upon the foot, if long continued, 
will cause an increase of thickness in the cuticle; 
such increase, when it presses so hard upon the 
ends of the nerves beneath as to cause pain, is a 
corn. A corn may be destroyed by cutting it thin 
with a knife and removing the pressure. 
Tight shoes will also cause in-growing toe nails, 
bunions, etc., all of which are veiy painful and 
interfere very much with the elasticity of step, 
and gracefulness of movement. 
Hosiery with holes in the toes or heels should 
be avoided, as they are liable to become wrinkled 
or folded in such a way as to bring on corns. 
Cleanliness of feet and foot-wear is essential to the 
health of the entire body as well as the feet. 
Rubbers should not be worn in the house, as 
they prevent the excretions of the feet from escap¬ 
ing. If these poisons do not escape they will be 
reabsorbed by the skin and thus injure the 
system. 
7. Ventilation .—(See breathing in Second Year 
work.) It is just as necessary for the lungs to be 
fed as it is for the stomach; and as the stomach 
requires pure and wholesome food, even so must 
the lungs have pure air. Air breathed over again 
