ioo THEORY OF FEEDING. 



brane of the alimentary canal. A portion of the common 

 salt in the system is used up in eliminating potash from the 

 body. Thus, as explained by Bunge, if a salt of potash, 

 such as carbonate of potash, meets common salt (chloride 

 of sodium) in solution, a partial exchange will take place by 

 the formation of chloride of potash and carbonate of soda ; 

 the chloride of potash being excreted by the kidneys, as it 

 does not enter into the composition of the tissues or fluids of 

 the body. 



Common salt stimulates digestion and all the other vital 

 processes of the body. The soda of the body, of which the 

 common salt of the food is the chief supplier, performs many 

 offices in the nourishment and purification of the system. 

 By combining with carbonic acid in the blood, it forms bicar- 

 bonate of soda, and thus helps to prevent the blood from 

 becoming overcharged with that hurtful gas. Lehmann points 

 out that an excess of carbonic acid in the blood tends to re- 

 dissolve the lime salts deposited at the growing ends of bones, 

 or prevents the precipitation of the lime salts. In agreement 

 with this theory, Wachsmuth contends that an accumulation 

 of carbonic acid in the blood is a cause of rickets. As 

 cartilage is much richer in soda than bone, and as young 

 animals have much more cartilage in their bodies than mature 

 ones ; they will need more soda in their food, and conse- 

 quently more common salt. According to Gabriel, bones and 

 teeth respectively contain 8 to 12 and I to 3 per cent, of 

 soda and potash. They require a large amount of soda to 

 neutralise the acids which might attack them. We all know 

 that the formation of bones and teeth is particularly active in 

 young animals. 



The consumption of too much salt causes a large discharge 

 of urine, irritation to the kidneys, and abnormal thirst, with a 

 consequent watery condition of the blood, from which the nutri- 

 tion of the system suffers. If drinking water be withheld, water 



