THE PRESENT PROBLEMS OF PHYSIOLOGICAL 



CHEMISTRY 



BY RUSSELL HENRY CHITTENDEN 



[Russell Henry Chittenden, LL.D. Sc.D., Director and Treasurer of the Sheffield 

 Scientific School, Yale University, and Professor of Physiological Chemistry. 

 b. February 18, 1856, New Haven, Connecticut. Ph.B. and Ph.D. Yale Uni- 

 versity; Special course, Heidelberg University. President of the American 

 Physiological Society, 1895-1904; President of the American Society of Natur- 

 alists, 1893. Member of the Connecticut Academy of Arts and Sciences; National 

 Academy of Sciences; American Philosophical Society. Author of many papers 

 on physiological subjects published in American and foreign journals.] 



IN considering a proper presentation of the subject assigned me, 

 I am impressed with the influence which a man's own field of work 

 and his own line of thought will naturally exercise upon his point of 

 view. It may be questioned whether his judgment can be wholly 

 trusted, whether he will not in fact, unconsciously it may be, give a 

 dwarfed or one-sided presentation of the subject from a natural habit 

 of looking at things in their bearing upon the line of work and thought 

 in which he himself is personally most interested. While this may 

 not be wholly undesirable, of still greater advantage will be a brief but 

 judicious presentation of all the more important problems that con- 

 front the physiological chemist of the present day ; but whether this 

 can be done satisfactorily in the time allotted is very questionable. 

 However, the effort will be made to emphasize, so far as the time will 

 allow, what to the writer seem the more significant and far-reaching 

 problems in physiological chemistry that call for speedy solution. 



Of fundamental importance is the question, what is the exact 

 chemical constitution of proteid matter? The basis of all cell-life, the 

 most complex molecule that enters into the structure of the living 

 organism, proteid or albuminous material holds a peculiar position. A 

 labile molecule, it is easily prone to change, and its many decomposi- 

 tion-products confront us on all sides in our study of life's processes. 

 Yet to-day, in spite of all that has been accomplished, even with the 

 brilliant work of Kossel and Emil Fischer, we still lack adequate 

 knowledge of all the groups and radicles that are combined in this 

 atomic complex. 



In the study of metabolism and nutrition, both in health and in 

 disease, in our conception of the anabolic processes of life, in our 

 theories regarding the chemical relationships of the varied katabolites 

 floating about through the organism, and in many other connections, 

 we need for our guidance a full knowledge of the chemical nature of 

 this most important class of substances. Thanks to the work of many 



