

CHAPTER II 

 ELEMENTS OF THE BODY 



18. Proximate principles. The cells of all animals con- 

 tain the same substances, differing in amount and arrange- 

 ment, yet alike in composition. The simple substances of 

 which the cells are composed are called proximate principles. 

 The most important proximate principles are water, albu- 

 min, fat ? sugar, salt, lime, soda, and potash. 



19. Water and solution. Water forms nearly three 

 fourths of the weight of the body and is present in every 

 part. It reaches each minute part of the body through 

 the firm walls of the organs. Water has the power of 

 dissolving solid substances, so that they retain all their 

 properties unchanged. Sugar in water is sugar still; in 

 fact, we can appreciate what sugar is only when it is dis- 

 solved. When a substance is dissolved in a liquid, so that 

 each remains unchanged in its essential properties, the 

 result is a solution. Most solutions will go anywhere 

 water itself will go. In the stomach the food becomes 

 dissolved, and is taken into the blood tubes. The blood 

 contains a solution of food which penetrates into the spaces 

 around each cell, carrying nourishment to the cell and 

 washing away its waste matters. Water makes the tissues 

 limber and slippery, so that they bend and move easily. 

 By means of the perspiration which carries off surplus heat, 

 water regulates the heat of the body. About three quarts. 

 of water are taken into the body each day. 



