392 Transactions of the Canadian Institute [vol. ix 



as being in a condition of inanition. This condition was varied by keep- 

 ing them in a warm room for some days and also by subcutaneous injec- 

 tions, into the dorsal lymph sac, of various diuretics. In some instances 

 the spinal cord had been previously cut. Details on these points are 

 given in the index to the Figures. The various anim.als used were 

 Necturus, frog, dog, cat, rabbit, and pigeon. 



III. Results. 



In the kidney from the inanition frog there were heavy condensa- 

 tions of potassium about the periphery of the tubules and at the margins 

 of their lumina (Fig. 2). Pract'cally no potassium was found in the 

 cytoplasm except in the region bordering on the lumen, although the 

 cellular outline was not sufficiently evident to state definitely in the 

 majority of instances whether it was within or without the cell. By 

 comparison, however, of a large number of preparations obtained under 

 different conditions the peripheral deposit was judged to be on the lymph- 

 tubule interface outside the cells, the central deposit being in the cyto- 

 plasm adjacent to the lumen. 



The active kidney did not differ quantitatively from the inactive 

 one, but the distribution of potassium was more uniform about the 

 periphery of the tubules and frequently about the lum.ina as well. This 

 was shown best in the frog under a mild dextrose diuresis (Fig. 3), also 

 in the frog under moderate sodium sulphate diuresis (Fig. 4). In the 

 latter the spinal cord had been cut previous to injection, to lower the 

 blood pressure so as to prevent a flow of urine and, consequently, the 

 actual localization of the potassium in the active kidney was mere evident. 

 The peripheral distribution can be clearly recognized as being external 

 to the tubule and the central as being in the cytoplasm bordering on 

 the lumen. 



In cases of excessive diuresis the conditions were less uniform, the 

 potassium, being found on the intercellular membranes, in che intra- 

 cellular spaces, on the surface of the nuclei, and, if the diuresis had been 

 induced by an injection of potassium salts, frequenc'y diffused through- 

 out the cytoplasm as well. This distribution was not associated with 

 any apparent increase in amount of potassium in the preparations from 

 the frog after excessive dextrose diuresis (Fig. 5), and also after excessive 

 sodium, sulphate diuresis (Fig. 6). No potassium was found through- 

 out the cytoplasm of the cells in these. The preparations from one of 

 these kidneys under excessive sodium sulphate diuresis showed curious 

 protrusions which by comparison with stained preparations were recog- 



