SECTION I. 



CHAPTER II. 



THE NUTRITIVES. 



INORGANIC ELEMENTS. WATER. AIR. SALTS. 



Composition of the Body. The living animal body is 

 composed in the mean of about 35 to 40 per cent of solids 

 and 60 to 65 per cent of water. In adults the solids are 

 somewhat in excess of this amount, while in infants they are 

 lower, perhaps not over 30 per cent. The elements most 

 abundantly present are carbon, oxygen, hydrogen, nitrogen, 

 phosphorus, sulphur, chlorine, potassium, sodium, calcium, 

 magnesium and iron. In traces only, or in particular tissues, 

 we find iodine, fluorine, bromine, silicon, manganese, copper 

 and lithium. The presence of these in minute amount seems 

 to be necessary for the existence of certain animals. These 

 elements are not present in the free state, but exist combined 

 in more or less complex compounds, the degree of complexity 

 varying between that illustrated in such simple bodies as water 

 or common salt, and that found in the large protein molecules 

 with possibly thousands of atoms present. 



In point of abundance these elements are found in the body 

 in about the following order : 



TABLE OF THE ELEMENTS IN THE BODY. 



