38 REPORTS ON THE STATE OF SCIENCE.—1918. 
face and there will be established a difference of potential between 
the ends of the capillaries. This difference in potential causes 
electrical endosmose to take place in one direction or the other and 
an apparent osmotic action results. That a difference of potential 
really does exist between the water side and the solution side of the 
diaphragm has been demonstrated experimentally. The explanation 
outlined above is an ingenious one, but the problem is by no means 
solved as yet.® 
SUMMARY. 
Electro-osmotic phenomena with pure liquids and solutions have 
been described and the various theories discussed critically. The 
most plausible hypothesis seems to be the Freundlich-Bancroft 
theory of selective ion adsorption. The effect of temperature 
changes and other influences have been considered and in conclusion 
mention has been made of negative osmosis and other phenomena 
related closely to electrical endosmose. Cataphoresis and electro- 
stenolysis have not been included. 
RECENT PAPERS ON ELECTRICAL ENDOSMOSE. 
‘ Electric osmosis and concentration of electrolytes. J.O.WAKELIN BARRATT and 
ALBERT B. Harris, Zeit. Hlektrochemie, 18, 221 (1912). 
Authors have studied electrical endosmose through diaphragms of gelatin, 
parchment and agar. Rate of flow and direction of osmose appear to be determined 
by the nature and valence of the ionsin solution. See next reference for more 
comprehensive article. 
‘ Electro-osmosis.. J.O. WAKELIN BARRATT and ALBERT B. HARRIS, Biochemical 
Jour., §, 315 (1916). 
See preceding reference. Article gives data for a large number of diaphragm 
substances, describes ingenious apparatus and discusses the hydration theory. 
Electro-osmose into human forearm studied. 
‘The effect of electrolytes on electrical endosmose.’ G. VON ELISSa¥FOFF, Zeit. 
Phys. Chem., 79, 385 (1912). ; 
Very important article showing where Perrin’s valence rule holds and where it 
fails. In an appendix written with Freundlich, the author argues very effectually 
in favour of the ionic adsorption theory. 
‘Electrical endosmose.’ WILDER D. BANCROFT, Jour. Phys. Chem., 16, 312 (1912) ; 
Trans. Am. Electrochem. Soc., 21, 233 (1912). 
Proposes ionic adsorption hypothesis and applies it to some hitherto unexplained 
experiments of REED, Zrans. Am. Electrochem, Soc., 2, 238 (1902). Article includes 
discussion of addition agents in electroplating. 
‘Determination of the valence of radium by means of electrical endosmose.’ 
HERBERT FREUNDLICH and G. VON ELISSAFOFF, Phys. Zeit., 14, 1052 (1913). 
Radium appears to be divalent and closely related to barium. Method depends 
upon application of Perrin’s rule and requires less than 0°01 milligram of 
substance. 
‘Hydration of organic colloids under the influence of electrolysis. E. DoUMER, 
Comptes rendus Soe. Bivol., "76, 40 (1914). 
Some curicus hydration and dehydration effects observed during electrical 
endosmose with gelatin. 
‘ Negative osmose.’ F. E. BARTELL, Jour, Am. Chem. Soc., 36, 646 (1914). 
Author accounts for positive and negative osmosis through porcelain by assuming 
that selective adsorption polarises the membrane and that the osmosis is really 
electrical endosmose. 
61 Cf. Bancroft, Jour. Phys. Chem., 21, 441 (1917). 
