Potassium in Kidney Cells. 



ii 



At the termination of the experiment small pieces of kidney- 

 tissue were removed, and frozen sections not over 20 micra in 

 thickness were made. The sections were treated at once with 

 Erdmann's 1 reagent as modified by Macallum 2 and used by him 

 in his studies "On the Distribution of Potassium in Animal and 

 Vegetable Cells." 



The reagent which consists in a solution of the hexanitrite of 

 cobalt and sodium serves as a complete precipitant of potassium 

 from its solutions, in the form of an orange-yellow precipitate of 

 the triple salt. If the salt is present in minute quantities the 

 crystalline form is absent. To render the detection of small 

 quantities of the salt possible, Macallum 3 used ammonium sulphide 

 to react with the cobalt of the salt and form the black sulphide of 

 cobalt which is easily detected. This suggestion of Macallum's 

 has been employed in the demonstration of potassium in all of 

 the sections. 



The results which have been obtained are as follows. 



1. The epithelial cells of the normal dog kidney show only 

 traces of potassium. The potassium is most marked in the loops 

 of Henle and is fairly evenly distributed throughout the cytoplasm 

 of the cells. It has never been demonstrated within the nucleus 

 of the normal cell. 



2. The epithelium of the nephropathic kidney shows an increase 

 in potassium over that of the normal. The potassium differs in 

 distribution within the cytoplasm of the cell and has been demon- 

 strated within the nucleus of the cell. 



3. The potassium in the nephropathic organs has been espe- 

 cially marked in the cells of the convoluted tubules. In the cyto- 

 plasm of the cells forming these tubules the potassium is not 

 uniformly distributed but is found to collect along the free margin 

 of the cells bordering the lumen of the tubule. A similar observa- 

 tion on the distribution of potassium salts was first made by 

 Macallum 4 in his studies of the frog kidney in which a decinormal 

 solution of potassium chloride was injected into the dorsal lymph 

 sacs of frogs. 



1 " Anorganische Chemie," 1898, p. 630. Reference given by Macallum. 

 1 Jour. Phys.. Vol. XXXII. No. 2. p. 98. 

 * hoc. cit. 



4 Science. Vol. XXXII, No. 824, p. 497. 



