844 METABOLISM. 



show that the carbonate cannot be replaced by an equivalent amount of 

 sodium chloride, and that to all appearances it acts by combining with 

 the acids formed in the body. The addition of alkali carbonate to the 

 otherwise nearly ash-free food may indeed delay death, but cannot pre- 

 vent it, and even in the presence of the necessary amount of bases death 

 results from lack of mineral substances in the food. 



With an insufficient supply of chlorides with the food the elimination 

 of chlorine by the urine decreases constantly, and at last it may stop 

 entirely, while the tissues still persistently retain the chlorides. It has 

 already been stated (Chapter IX) how chloride starvation influences other 

 functions, especially the secretion of gastric juice. If there be a lack of 

 sodium as compared with potassium, or if there be an excess of potassium 

 compounds in any other form than KC1, the potassium combinations are 

 replaced in the organism by NaCl, so that new potassium and sodium 

 compounds are produced which are voided with the urine. The organism 

 becomes poorer in NaCl, which therefore must be taken in greater amounts 

 from the outside (BUNGE). This occurs continuously in herbivora, and in 

 man with vegetable food rich in potash. For human beings, and espe- 

 cially for the poorer classes of people who chiefly live on potatoes and 

 foods rich in potash, common salt is, not only a condiment, but a 

 necessary addition to the food (BUNGE J ). On the behavior of chlorides, 

 especially sodium chloride, in the animal body as well as the elimination 

 or the retention of NaCl in diseases we have an abundance of investiga- 

 tions, which may be found in ALBU and NEUBERG'S work, previously 

 cited. 



Lack of Alkali Carbonates or Bases in the Food. The chemical processes 

 in the organism are dependent upon the presence of tissue-fluids of a cer- 

 tain reaction, and this action, which is habitually alkaline toward litmus 

 and neutral toward phenolphthalein, is chiefly due to the presence of 

 alkali carbonates and carbon dioxide and in a lesser degree to alkali 

 phosphates. The alkali carbonates are also of great importance, not 

 only as a solvent for certain protein bodies and as constituents of cer- 

 tain secretions, such as the -pancreatic and intestinal juices, but they 

 are also a means of transportation of the carbon dioxide in the blood. 

 It is therefore easy to understand that a decrease below a certain point 

 in the quantity of alkali carbonate must endanger life. Such a decrease 

 not only occurs with lack of bases in the food which brings about various 

 disturbances and death by a relatively great production of acids through 

 the burning of the proteins, but it also occurs when an animal is given 

 dilute mineral acids for a period. The importance of ammonia as a 

 means of neutralizing the acids produced or introduced into the body 



1 Zeitschr. f . Biologic, 9. 



