snip the outer shell membrane, thus opening the space between the outer and inner membranes.  Now put the egg into a glass of water, keeping it in an upright position by resting on a napkin-ring.  There is only the inner shell membrane between the liquid white of the egg (albumen) and the water.

  An interchange takes place, and the water passes towards the albumen.  As
  the albumen does not pass out freely towards the water, the membrane
  becomes distended, like a little bag at the top of the egg.

162.  Ill Effects of a too Generous Diet.  A generous diet, even of those who take active muscular exercise, should be indulged in only with vigilance and discretion.  Frequent sick or nervous headaches, a sense of fullness, bilious attacks, and dyspepsia are some of the after-effects of eating more food than the body actually requires.  The excess of food is not properly acted upon by the digestive juices, and is liable to undergo fermentation, and thus to become a source of irritation to the stomach and the intestines.  If too much and too rich food be persistently indulged in, the complexion is apt to become muddy, the skin, especially of the face, pale and sallow, and more or less covered with blotches and pimples; the breath has an unpleasant odor, and the general appearance of the body is unwholesome.

An excess of any one of the different classes of foods may lead to serious results.  Thus a diet habitually too rich in proteids, as with those who eat meat in excess, often over-taxes the kidneys to get rid of the excess of nitrogenous waste, and the organs of excretion are not able to rid the tissues of waste products which accumulate in the system.  From the blood, thus imperfectly purified, may result kidney troubles and various diseases of the liver and the stomach.

163.  Effect of Occupation.  Occupation has an important influence upon the quantity of food demanded for the bodily support.  Those who work long and hard at physical labor, need a generous amount of nutritious food.  A liberal diet of the cereals and lean meat, especially beef, gives that vigor to the muscles which enables one to undergo laborious and prolonged physical exertion.  On the other hand, those who follow a sedentary occupation do not need so large a quantity of food.  Brain-workers who would work well and live long, should not indulge in too generous a diet.  The digestion of heavy meals involves a great expenditure of nervous force.  Hence, the forces of the brain-worker, being required for mental exertion, should not be expended to an unwarranted extent on the task of digestion.

164.  Effect of Climate.  Climate also has a marked influence on the quantity of food demanded by the system.  Much more food of all kinds is consumed in cold than in warm climates.  The accounts by travelers of the quantity of food used by the inhabitants of the frigid zone are almost beyond belief.  A Russian admiral gives an instance of a man who, in his presence, ate at a single meal 28 pounds of rice and butter.  Dr. Hayes, the Arctic traveler, states from personal observation that the daily ration of the Eskimos is 12 to 15 pounds of meat.  With the thermometer ranging from 60 to 70 degrees F. below zero, there was a persistent craving for strong animal diet, especially fatty foods.[24]