402 Transactions of the Canadian Institute [vol. ix 



0.02I2 per cent, of potassium. The value* Na(= lOo) : K of the blood 

 would, therefore, be loo : 7.8. The quantitative composition of dog's 

 lymph has not been determined, but it cannot be very different from 

 blood plasma and serum, so far as the inorganic constituents are con- 

 cerned, and in the serum according to Abderhalden's analyses the sodium 

 and potassium are 0.3175 and 0.0217 per cent, respectively, or in the 

 proportion of 100 : 6.8. 



If, therefore, the dog's kidney could, before analysis, be freed of 

 all its blood and lymph, it would show a very considerable excess of 

 potassium over sodium. It would be much more than ten times richer 

 in potassium than the blood or blood plasma, while it would contain 

 much less sodium than the blood or blood plasma. 



No analyses have been published giving the composition of the 

 blood in the frog, and consequently one cannot determine whether the 

 retention of blood or lymph in the frogs' kidneys analyzed influenced 

 very materially the analyses, but, on comparison with the results fur- 

 nished by the analyses of the dogs' kidneys, it would appear as if there 

 were no important difference between the two series of analyses in 

 regard to the potassium. 



The kidney is not the only organ in which potassium is richer than 

 sodium. Katz^^ found that in the striated muscle of the dog potassium 

 is three and a half times as abundant as the sodium, and Stoklasa^" 

 determined that the dried pancreas of the pig contains 2.08 per cent, 

 of potassium and 0.28 per cent, of sodium. It is also known from 

 Geoghegan's^® analyses that potassium in brain tissue exceeds the sodium 

 in amount. 



In muscle certainly and probably in the pancreas the metabolic 

 processes are very active. In striated muscle fibre Macallum has 

 shown that the potassium is confined to the doubly refractive portion 

 of the sarcous elements in which, there is reason to believe, the chief 

 metabolic processes of the fibres occur. It is not at all unlikely that 

 potassium plays a part in these processes, and that in the pancreas a 

 similar r61e is filled by the element. In the active kidney, as shown 

 by its consumption of oxygen, the metabolism is very pronounced, and 

 consequently it may be suggested that here, also, the potassium so 

 abundantly present is in some manner associated with that metabolism. 



One must not, however, exclude the possibility that potassium is 

 so abundant in tissues simply because of a special tendency to condense 

 on surfaces of systems affected by low surface tension. From Lewis' 



* Calculated from Abderhalden's values which were given for Na20 and KjO 

 respectively. 



