SCIENCE 



Friday, January 28, 1921 



CONTENTS 

 Electrification of Water and Osmotic Flow: 

 Dr. Jacques Loeb 77 



Henry Andrews Bumstead: Peopessob E. A. 

 MiLLIKAN 84 



■ Events: — 

 Polar Research; Anthropological Publica- 

 tions of the Canadian Arctic Expedition; 

 Administration of the Alaslca Forests; Fish- 

 ery Matters in Congress; The Washington 

 Academy of Sciences; Samuel J. Meltzer. 85 



Scientific Notes and News 88 



University and Educational News 90 



Discussion and Correspondence: — 



A Meteor Fall in the Atlantic: Henet S. 

 Washington. Musical Notation: Db. T. P. 

 Hall. Pulsation of a Cat's Heart after 

 Death: De. Hoeace Gunthoep. Stoch Cul- 

 tures of a Protozoan : De. Joseph H. Bodine. 90 



Tlie British Committee for Aiding Men of 

 Letters and Science in Su^sia 93 



Special Articles: — 

 Star Time Observations with an Engineer's 

 Y-Level: Db. Willaed J. Fishbb 94 



The American Society of Naturalists: Peo- 

 fessob a. Feanklin Shull 95 



The American Society of Zoologists: Pbo- 

 PESSOE W. C. Allee 97 



MSS. intended for publication and books, etc., intended for 

 review should be sent to The Editor of Science, Garrison-on- 

 Hudson, N. Y. 



ELECTRIFICATION OF WATER AND 



OSMOTIC FLOWi 



I 



The exciiange of water and solutes between 

 the cell and the surrounding fluid is one of 

 the important factors in the mechanism of 

 life, and a complete theory of the osmotic 

 flow is therefore a postulate of biology. It 

 was a marked advance when the experiments 

 of Pfeffer and de Vries led van't Hofi to the 

 formulation of the modern theory of osmotic 

 pressure. According to this theory the mole- 

 cules of the solute behave like the molecules 

 of a gas in the same volume and at the same 

 temperature, and the gas pressure of the 

 solute measures the " attraction " of a watery 

 solution for pure water through a strictly 

 semipermeable membrane. Yet it is obvious 

 to-day that in a liquid the electrical forces 

 between solvent and solute must play a role 

 and no adequate provision is made i'or these 

 forces in van't Hoff's law. Traube rejected 

 van't Hoff's theory altogether, suggeiiting in- 

 stead that the osmotic flow was from the 

 liquid with lower to the liquid with higher 

 surface tension (and higher intrinsic pres- 

 sure). 



Tinker has shown that van't Hoff's theory 

 for osmosis holds strictly only in the case of 

 ideal solutions, i.e., when the process of solu- 

 tion occurs without heat of dilution and 

 change in volume, but that in the case of 

 non-ideal solutions Traube's ideas explain the 

 deviations from the gas law which are bound 

 to occur. When two different ideal solutions 

 containing equal numbers of particles of 

 solute in equal volume are separated by a 

 strictly semipermeable membrane, equal num- 

 bers of molecules of water will diffuse simul- 



1 Presidential address prepared for the CMcago 

 meeting of the American Sosiety of Naturalists, 

 December 30, 1920. 



