BIOLOGY IN HUMAN AFFAIRS 



The German physiologist, Rubner, proved that a human 

 being could lose 40 per cent of his body weight and still re- 

 cover; but that serious trouble would follow a 10 per cent 

 loss of water in the body, and that death after the loss of 

 20 per cent was certain. Obviously, the control of such an 

 important substance in the human body, through the thou- 

 sands of years in which the human being has developed, 

 had to become an automatic procedure. 



A person in good health is quite able to regulate the 

 amount of water that he drinks. However, a man who is 

 unconscious owing to brain hemorrhage, or who is para- 

 lyzed and unable to help himself, or who is ill in any 

 manner which prevents him from satisfying his thirst, 

 has to be looked after by some one else who must see to it 

 that the supply of water is regularly maintained. Un- 

 doubtedly, in many instances of skull fracture or of brain 

 hemorrhage or of shock, people have died because a 

 sufficient amount of water was not available. 



It has been estimated by several investigators that the 

 amount of water put in represents about two quarts per 

 day, usually taken in the form of drinking water; of water 

 in coffee, milk, and soup; of water in solid foods; and of 

 water developed by chemical changes within the body. It 

 has been estimated that the amount of water passing 

 out each day represents a relatively similar amount, short 

 of about one-half pint. The water put out is in the usual 

 excretions of the body, and particularly in water vaporized 

 through the skin and through breathing. 



The average man ought to drink at least eight glasses 

 of water a day. He seldom realizes, however, that many 

 of the foods that he takes must also supply additional 

 water. Such apparently solid foods as steak, eggs, potatoes, 

 oysters, tomatoes, asparagus, celery, and lettuce contain 

 from 75 to 95 per cent of water. 



[220] 



