452 PHYSIOLOGICAL CHEMISTRY. 



the organic substances which retain them. The great importance 

 of such a retention of chlorides *by the tissues is apparent if we bear 

 in mind that the NaCl is not only a solvent for certain albuminous 

 bodies, or a material for the elaboration of the gastric juice, but 

 that it is also of the greatest importance as a so-called indifferent 

 salt for the preservation of the normal consistency and the physio- 

 logical imbibition relation of the tissues. 



If there be a lack of sodium as compared to potassium, also 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 habitually in herbivora, and in man 

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

 especially for the poorer classes of people who live chiefly on pota- 

 toes and foods rich in potash, common salt is, under these circum- 

 stances, not only a condiment, but a necessary addition to the food 



(BUKGE). 



Lack of alkali carbonates or bases in the food. The chemical 

 processes in the organism are dependent upon the presence of 

 alkaline-reacting tissue-fluids, whose alkaline reaction is due to 

 alkali carbonates. The alkali carbonates are also of great impor- 

 tance not only as a solvent for certain albuminous bodies and as 

 constituents of certain secretions, as of the pancreatic and intes- 

 tinal 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 car- 

 bonate must endanger life. Such a decrease not only occurs with 

 lack of bases in the food which accelerates death by a relatively too 

 great production of acids by the burning of the proteids (see above: 

 BUNGE and LUKIN), but it also occurs when an animal is given 

 dilute mineral acids for a certain time. In herbivora the fixed 

 alkalies of the tissues combine with the mineral acids, and the 

 animal succumbs after a time. In carnivora the bases of the tis- 

 sues are obstinately retained; the mineral acids unite with the 

 ammonia produced by the decomposition of the proteids or their 



