ACKNOWLEDGMENT. 



It gives me great pleasure to thank Prof. William J. Gies 

 for suggesting this problem and for his constant supervision of 

 the work. 



Throughout the four years I rfkve been in his laboratory 

 he has been ever ready to give me the benefit of his time and 

 wide knowledge, notwithstanding the pressure under which 

 he has to work. 



Through his influence I am enabled to continue along re- 

 search lines, and to his teaching and example I owe whatever I 

 may be able to produce as a contribution to Experimental 

 Medicine. JACOB ROSENBLOOM. 



LABORATORY OF BIOLOGICAL CHEMISTRY OF 



COLUMBIA UNIVERSITY, AT THE 



COLLEGE OF PHYSICIANS 



AND SURGEONS, 



NEW YORK. 



May, 1909. 



