SCIENCE 



Friday, October 15, 1915 



CONTENTS 

 The Physiological Importance of Phase Bound- 

 aries: Professor "W. M. Bayliss 509 



The Publication of the Sesults of Investiga- 

 tions made in Experiment Stations in Tech- 

 nical Scientific Journals: Dr. Eaymond 

 Pearl 518 



The Naval Consultation Board 522 



Scientific Notes and News 523 



University and Educational News 526 



Discussion and Correspondence: — 

 Potassium from the Soil: Professoe E. W. 

 HiLGARD. Elementary Mechanics: Peo- 

 PESSOE Edwin Bidwelij Wilson. The End 

 is not yet : Dr. Wither Stone. The ' ' Pan- 

 American Scientific Congress" : H. A 527 



Scientific BooTcs: — 

 Siley and JoJiannsen's Medical Entomol- 

 ogy: W. H. Hdntee. Abderhalden on 

 Aiwehrfermente : Dr. John Auer. Olcott's 

 Sun-lore of All Ages: Peopessok Chas. 

 Lane Pooe 531 



HemoglobinophiUc Bacteria: Dr. David John 

 Davis 532 



Special Articles: — 



Artificial Daylight for the Microscope: 

 Professoe Simon H. Gage. A New Alfalfa 

 Leaf -spot in America: Leo E. Melchees. 

 Differentiation of Wandering Mesenchymal 

 Cells in the Living Yolk-sac: Dr. C. E. 

 Stockaed 534 



Anthropology at the San Francisco Meeting: 

 Professor George Grant MacCwrdy .... 541 



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

 review should be sent to Professor J. McKeen Cattell, Garrison- 

 On-Hudson. N. Y. 



THE PSYSIOLOGICAL IMPORTANCE OF 

 PEASE BOUNDARIES-^ 



Even a hasty consideration of the ar- 

 rangements present in living cells is suffi- 

 cient to bring conviction that the physical 

 and chemical systems concerned operate 

 under conditions very different from those 

 of reactions taking place between substances 

 in true solution. We become aware of the 

 fact that there are numerous constituents 

 of the cell which do not mix with one an- 

 other. In other words, the cell system is 

 one of many "phases," to use the expres- 

 sion introduced by Willard Gibbs. 



Further, parts of this system which ap- 

 pear homogeneous under the ordinary 

 microscope are shown by the ultra-micro- 

 scope to be themselves heterogeneous. 

 These are in what is known as the colloidal 

 state. Some dispute has taken place as to 

 whether this state is properly to be called 

 a heterogeneous one, but it is sufficient for 

 our purpose to note that investigation shows 

 that the interfaces of contact between the 

 components of such systems are the seat 

 of the various forms of energy which we 

 meet with in the case of systems obviously 

 consisting of phases which can be separated 

 mechanically, so that considerations apply- 

 ing to coarsely heterogeneous systems apply 

 also to colloidal systems. Although the 

 phases of a colloidal system can not be so 

 obviously and easily separated as those of 

 an ordinary heterogeneous one, this can be 

 done almost completely by iiltration 

 through membranes such as the gelatin in 



1 Address of tbe President of the Section of 

 Physiology at the Manchester Meeting of the 

 British Association for the Advancement of Sei- 



