X ELECTROLYTES IN BIOLOGICAL SYSTEMS 



Another importanl aspect of the approach employed by Dr. Jacobs and Dr. 

 Osterhout has been the appHcation of quantitative methods. Precision is of 

 inestimable importance in sharply delimiting possible mechanisms, for on 

 purely qualitative grounds many more hypotheses must usually be entertained. 

 This is evident throughout the present volume. 



The collective work of Dr. Osterhout and Dr. Jacobs emphasizes the two 

 features of electrolyte distribution which current studies are attempting to dis- 

 criminate — the "passive", governed by electrochemical forces, and the "ac- 

 tive", directly dependent on continuous energy expenditure by the cell. The 

 techniques for distinguishing these are still far from fully developed, but Shanes 

 and Tosteson point out that the prospects are promising. Under the circum- 

 stances, special terms like "transport", which are now so popular and which are 

 subject to misuse, should be avoided in favor of more general expressions unless 

 indisputable evidence justifies their application. 



The Society of General Physiologists is indebted to the National Science 

 Foundation for underwriting this volume. The editor is especially grateful to 

 Dr. Louis Levin and Dr. John Buck for their advice and encouragement, to 

 Professor Wallace O. Fenn and to Dr. Milton O. Lee, whose interest and efforts 

 contributed so substantially to publication of the monograph, and to the au- 

 thors for their wholehearted cooperation 



