150 PHYSIOLOGY. 



this is now attributed to a diet of fat and salt meat, to the 

 exclusion of fresh vegetables, vegetable acids, etc. The 

 disease is avoided by a greater use of vegetables, lime 

 juice, etc. 



Fruits. Many of the fruits, such as bananas and 

 apples, have considerable starch and sugar. But the 

 fruits are probably more useful to us on account of their 

 flavor, due to aromatic bodies, and to their salts and the 

 peculiar fruit acids. 



Water. Water constitutes about two thirds of the 

 entire weight of the body. It constitutes the bulk of the 

 liquids we have studied, blood, lymph, sweat, saliva, bile, 

 etc. Water is the solvent and carrier of all the material 

 of the body. Hence we need a large amount of it ; of 

 course we must remember that we get a good deal of water 

 in most of our solid foods. 



Rain Water. Water, as it comes from the clouds, is 

 pure. After enough rain has fallen to wash the air, rain 

 water is pure, and if caught on a clean roof (especially a 

 slate roof) and kept in a clean cistern, it is good drinking 

 water. 



Well Water. Falling upon the earth, the rain water 

 soaks down until stopped by some impervious layer, such 

 as clay. This water is the supply of our wells and springs. 

 It always has more or less earthy matter in solution, and 

 is therefore more or less " hard." Unless a large amount 

 of mineral matter or some special material is dissolved in 

 it, it is, ordinarily, good drinking water. Such water is 

 not pure, in the strict sense of the word, but is pure for 

 drinking purposes. 



