i EXCHANGE OF MATEKIAL 45 



removal of the urea formed by the liver. If we extend the 

 research by drinking a larger quantity of water to make up for 

 the greater quantity discharged, we shall find that the sodium 

 chloride not only does not increase the consumption of nitrogen, 

 but may slightly reduce it. 



We would finally point out that the continued abuse of sodium 

 chloride, as, for instance, a daily diet consisting mainly of salt 

 meat, by increasing the flow of urine causes an increase in the 

 quantity of lime discharged in the urine, and produces an out- 

 break of scurvy. 1 



With regard to the functional importance of the different 

 components of vegetable and animal ashes, it should be noted that 

 the introduction of a considerable quantity of calcium, magnesium, 

 sodium, and phosphorus is necessary for the formation of the 

 bones and cartilages, and potassium and phosphorus are further 

 necessary for the development of the muscles and probably the 

 protoplasm of all cells. 



The long time which the excised heart can be made to survive 

 by perfusion with oxygenated Kinger's solution, as compared with 

 the ordinary physiological solution of sodium chloride, proves the 

 importance of potassium and lime for muscular activity and 

 protoplasmic movements in general. A small quantity of potas- 

 sium and lime is also indispensable for the development of the 

 fertilised ovum (J. Loeb). A pure solution of sodium chloride is 

 poisonous without the addition of about 2 per cent of lime and 

 potassium. 



Phosphorus is found in articles of food in the form of lecithine, 

 phosphoprotein (casein, vitelline), and nucleoproteins which form 

 the chemical basis of the nuclei of cells. It is almost superfluous 

 to remark that these nutritive products are indispensable to the 

 organism at every stage of life, and more especially during the 

 anaplastic period. Numerous researches prove that these organic 

 compounds of phosphorus, which are contained in large quantities 

 in vegetable and animal foods, are of considerably greater 

 nutritive value than the mineral phosphates contained in the 

 bones (Danilewski, Cronheim, Mliller). On the other hand, the 

 value of sodium, potassium, calcium, magnesium, and chlorine is 

 the same whether found in the form of organic compounds or 

 simple mineral salts. 



During complete or partial abstinence from salts, there is for 

 the first few days a large excretion of salts, but later the quantity 

 expelled becomes steadily smaller, because the salts are firmly 

 combined with the organic molecules of the protoplasm of the 

 tissues. When the normal diet containing a sufficient quantity 

 of salts is resumed, the salts are partly retained in the impoverished 



1 There is evidence that scurvy is due to the absence of an accessory food 

 factor (vitamine). See p. 49. 



