that children should be hardened by exposure to the cold.  Judicious “hardening” means ample exposure of well-fed and well-clothed children.  Exposure of children not thus cared for is simple cruelty.  The many sicknesses of children, especially diseases of the throat and lungs, may often be traced directly to gross carelessness, ignorance, or neglect with reference to undue exposure.  The delicate feet of children should not be injured by wearing ill-fitting or clumsy boots or shoes.  Many deformities of the feet, which cause much vexation and trouble in after years, are acquired in early life.

No one should sleep in any of the clothes worn during the day, not even in the same underclothing.  All bed clothing should be properly aired, by free exposure to the light and air every morning.  Never wear wet or damp clothing one moment longer than necessary.  After it is removed rub the body thoroughly, put on at once dry, warm clothing, and then exercise vigorously for a few minutes, until a genial glow is felt.  Neglect of these precautions often results in rheumatism, neuralgia, and diseases of the chest, especially among delicate people and young women.

Pupils should not be allowed to sit in the schoolroom with any outer garments on.  A person who has become heated in a warm room should not expose himself to cold without extra clothing.  We must not be in a hurry to put on heavy clothes for winter, but having once worn them, they must not be left off until milder weather renders the change safe.  The cheaper articles of clothing are often dyed with lead or arsenic.  Hence such garments, like stockings and colored underclothing, worn next the skin have been known to produce severe symptoms of poisoning.  As a precaution, all such articles should be carefully washed and thoroughly rinsed before they are worn.

The Kidneys.

254.  The Kidneys.  The kidneys are two important organs in the abdomen, one on each side of the spine.  They are of a reddish-brown color, and are enveloped by a transparent capsule made up of a fold of the peritoneum.  Embedded in fat, the kidneys lie between the upper lumbar vertebrae, and the crest of the hip bone.  The liver is above the right kidney, and the spleen above the left, while both lie close against the rear wall of the abdomen, with the intestines in front of them.  The human kidneys, though somewhat larger, are exactly of the same shape, color, and general appearance as those of the sheep, so commonly seen in the markets.

The kidneys are about four inches long, two inches across, one inch thick, and weigh from 41/2 to 51/2 ounces each.  The hollow or concave side of the kidneys is turned inwards, and the deep fissure of this side, known as the hilus, widens out to form the pelvis.  Through the hilus the renal artery passes into each kidney, and from each hilus passes outwards the renal vein, a branch of the inferior vena cava.

A tube, called the ureter, passes out from the concave border of each kidney, turns downwards, and enters the bladder in the basin of the pelvis.  This tube is from 12 to 14 inches long, about as large as a goose quill, and conveys the secretion of the kidneys to the bladder.