54 ELEMENTS OF PHYSIOLOGY 



Starch and the cellulose of wood are different forms of the 

 same chemical substance. Wood cannot be used in the body, 

 and starch must be changed to sugar before it can become 

 a part of the body. Very little sugar is found in the body 

 at one time, as it is constantly used to produce warmth. 

 About five ounces of sugar or starch should be eaten each 

 day in winter, and less in summer and in warm climates. 



89. Other Substances. There are about six ounces of 

 salt in the human body. We do not give salt to a pet cat 

 because it gets salt in the flesh it eats ; but we give salt 

 to the cattle because there is not enough in vegetable food 

 to supply their needs. Salt gives an agreeable taste to 

 food and helps to keep the albumin of the body dissolved ; 

 when salt is not used, weakness results. 



90. There are about ten pounds of lime in the human 

 body. The lime is deposited around the cells of the bones 

 to give stiffness to the bones. 



91. Soda and potash are called alkalies. A substance 

 which corrodes metals, is sour to the taste and unites with 

 soda or potash, is called an acid. Vinegar is an acid 

 substance; when soda is added to it, both are changed, and 

 the liquid resulting has a flat, bitter taste. Thus acids and 

 alkalies neutralize each other. Saliva is formed in the mouth 

 and is alkaline. The gastric juice of the stomach is acid. 

 The blood is alkaline and performs the function of destroy- 

 ing irritating acids in the body by neutralizing them. 



92. The human body is built up of 13 of the 70 or more 

 elements. The 13 elements are compounded into substances 

 which make up the body of a man weighing 1 50 pounds, 

 in the following proportions : 



92 pounds of water. I pound of carbonate of lime. 



21 pounds of fat. 6 ounces of phosphate of magnesium. 



1 8 pounds of dry proteid. 2-3 ounces of common salt and chlorid 



9 pounds of gelatin. of potassium. 



8| pounds of phosphate of lime. 3 ounces of sugar and animal starch. 



As much iron as there is in four carpet tacks. 



