534 Prof. A. B. Macallum. Acineta tuberosa : [Feb. 19, 



in the living cell. Further, between each cell of a tissue or organ and the 

 lymph that bathes its surface there is an interface where the salts of the 

 lymph may lower the surface tension, and in consequence undergo more or 

 less of condensation there. This serves to lower the general concentration in 

 the lymph, and the osmotic pressure is diminished accordingly. 



That such surface and interfacial condensations of solutes in living tissues 

 and organs can occur, and thus modify the distribution of their soluble 

 constituents, though definitely indicated by the results of physical investiga- 

 tions, would largely remain of theoretical interest if there were not more 

 direct evidence to this effect. Such direct evidence comes from investigation 

 by microchemical methods of the distribution of salts in living cells. The 

 microchemical localisation of salts in cells and tissues is as yet not advanced 

 enough to enable us to determine the finer distribution in living structures 

 of all its inorganic constituents, but along several lines it is complete enough 

 to permit us to demonstrate a condensation of salts due to the action of the 

 Gibbs-Thomson principle. 



This localisation is most effective in the case of the potassium salts. 

 Eight years ago the author found that the hexanitrite of cobalt and sodium 

 represented by the formula CoNa3(lSr02)6, in an appropriately prepared 

 solution, instantaneously precipitates potassium from its solutions as 

 Co(N0 2 ).3,3(K/Na)N0 2 + '»H20, in which the amount of the potassium 

 ranges, according to K. Gilbert's (4) determinations, from 16"31 to 18 - 21 

 per cent. The sensitiveness of the reaction may be understood from the 

 fact that, in a solution so dilute as 1 part of potassium in 275,000 parts of 

 a solution formed chiefly of the reagent, the crystals of the triple salt, the 

 hexanitrite of cobalt, sodium, and potassium, are formed. 



In tissues the potassium is not always abundant enough to give with the 

 reagent crystals of the triple salt, and in the vast majority of preparations 

 the triple salt formed is evident only as a yellowish reaction, and, conse- 

 quently, not sharply delimited in tissue preparations. If, however, the 

 reagent is completely washed out of the preparation with ice-cold water, the 

 application of ammonium sulphide, reacting as it does to form the black 

 cobaltous sulphide, brings out, in an extraordinarily sensitive way, the 

 distribution of the triple salt, and, therefore, of the potassium in it. This 

 black reaction, as observed under the microscope, makes the distribution of 

 the triple salt sufficiently sensitive to diagnose the presence of potassium 

 when it is but 1 part in over 1,000,000 of tissue mass. 



With this method of localising the distribution of potassium, the author 

 succeeded in finding that, in a number of animal and vegetable cells, the 

 potassium is condensed on surfaces in such a way as to make it very highly 



