900 METABOLISM. 



substances by man as very small. It may, however, be assumed that 

 man usually takes with his food a considerable excess of mineral sub- 

 stances. 



Experiments to determine the results of an insufficient supply of 

 mineral substances with the food in animals have been made by several 

 investigators, especially FCRSTER. He observed, on experimenting with 

 dogs and pigeons with food as poor as possible in mineral substances, 

 that a very suggestive disturbance of the functions of the organs, par- 

 ticularly the muscles and the nervous system, appeared, and that death 

 resulted in a short time, earlier in fact than in complete starvation. On 

 observations made upon himself, TAYLOR l found on partaking less than 

 0.1 gram salts per diem that the chief disturbance occurred in the mus- 

 cular system. 



BUNGE in opposition to these observations of FORSTER'S has suggested 

 that the early death of these cases was not caused by the lack of mineral 

 salts, but more likely by the lack of bases necessary to neutralize the sul- 

 phuric acid formed in the combustion of the proteins in the organism; 

 these bases must then be taken from the tissues. In accordance with 

 this view, BUNGE and LuNiN 2 also found, in experimenting with mice, 

 that animals which received nearly ash-free food with the addition of 

 sodium carbonate were kept alive twice as long as those which had the 

 same food without the sodium carbonate. Special experiments also 

 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 VIII) 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 com- 

 binations 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 



1 University of California Publications, Pathol., 1. 



2 Bunge, Lehrbuch der physiol. Chem., 4. Aufl., 97; Lunin, Zeitschr. f. physiol. 

 Chem., 5. 



