74 PHYSIOLOGY FOR NURSES 



the experiment was tried 011 a large scale in France, 

 but this experiment was a failure, for the reason already 

 given. 



The mineral salts are absolutely indispensable in the 

 diet, and it is stated that death will occur in an animal 

 fed on an abundance of salt-free food sooner than with 

 one deprived entirely of all food. This is because the 

 organic food leads to the excretion of the salts in the 

 tissues. 



Sodium chloride, or ordinary salt, is the only one of 

 the salts that we consciously add to our diet. When the 

 diet consists of a considerable amount of vegetable food, 

 the need of sodium chloride becomes more apparent, and 

 herbivorous animals show the same desire for salt that 

 human beings do. 



The sodium chloride plays a very important role in 

 our bodies. It is the chief inorganic constituent of our 

 blood plasma and it is essential for the production of 

 hydrochloric acid of the gastric juice. It is also sup- 

 posed to exert an influence on the contractions of the 

 heart. The urine contains a considerable amount of 

 this salt, and in certain cases of diseased kidneys, diffi- 

 culty is experienced by these organs in eliminating the 

 sodium chloride. As a result of this, there occurs a 

 salt retention and the salt also retains fluid, giving rise 

 to the accumulation of fluid in the tissues, known as 

 edema or dropsy. 



Salts of calcium are also important. They influence 

 the contraction of the heart and also the irritability of 

 muscle and nerve. Calcium is found in large amounts in 

 the bones, and clotting of blood and curdling of milK 

 can not take place in the absence of calcium. Potassium 

 salts influence the heart, while the salts of iron are of 



