FOREWORD 



The clinical studies on normal and hypertensive subjects 

 reported here have been conducted as a collaborative pro- 

 gram of the Department of Medicine and the Department 

 of Physiology of New York University College of Medicine. 



The author is indebted to Dr. William Goldring, Dr. 

 Herbert Chasis and Dr. Hilmert A. Ranges for the oppor- 

 tunity to describe unpublished observations. 



