X INTRODUCTION 



Once again, as in the publication of the last annual symposium on Electro- 

 lytes in Biological Systems, edited by A. M. Shanes, we are indebted to the 

 American- Physiological Society and especially to the Board of Publication 

 Trustees for its good offices in seeing the symposium into print. 



Theodore H. Bullock 

 Woods Hole, Summer, 1956. 



