x PREFACE 



collaboration in the research upon the chemical con- 

 stituents of various organs of animals under condi- 

 tions of activation; and to Dr. W. J. Crozier for 

 reading the manuscript and for valuable suggestions. 



To my associate, Dr. W. E. Lower, I am heavily 

 indebted for the invaluable assistance he has given 

 me throughout the entire research 



To Miss Annette Austin I wish to express my 

 special appreciation of her great assistance in com- 

 piling the data from my various monographs, manu- 

 scripts, and papers, as well as from the literature ; 

 and of her aid in their presentation in the following 



pages. 



GEOKGE W. CEILE. 



GUSHING LABORATORY OF EXPERIMENTAL MEDICINE, 



WESTERN RESERVE UNIVERSITY, 



January 1, 1915. 



