February 14, 1908] 



SCIENCE 



243 



ical side of physiology, since the physical 

 side has been found inadequate to explain 

 all the varied phenomena of living organ- 

 isms. As a result, physiological chemistry 

 has developed by leaps and bounds, until 

 to-day special laboratories and journals de- 

 voted to this subject are to be found on 

 all sides. 



Again, in bacteriology, and in medicine 

 in general, the applications of chemistry 

 are so numerous and so fruitful in results 

 that it is no longer necessary to defend the 

 position of physiological or biological 

 chemistry as a leading factor in the de- 

 velopment of knowledge in these subjects. 

 Sooner or later, in almost every problem 

 that presents itself, we are brought face to 

 face with some form of chemical reaction, 

 or some chemical substance, upon which 

 hinges the explanation of the phenomenon 

 in question. Under the broad term of 

 biological chemistry, we are dealing with a 

 subject which, directly and indirectly, con- 

 cerns itself with the chemical processes of 

 living organisms, and as these are as many 

 and varied as the organisms themselves, it 

 is plain to see that the field is broad and 

 one beset with many difficulties. 



The very breadth of our field makes it 

 clear that there will be diversity of opinion 

 regarding the relative importance of the 

 present-day problems in our science. To 

 one man, quite naturally, a certain line of 

 investigation wiU appeal most strongly, 

 while to another a totally different set of 

 problems will be suggested as the more im- 

 portant and promising. To one, questions 

 of chemical structure and their bearing 

 upon the processes of metabolism will 

 prove most attractive; to another, ques- 

 tions of physico-chemical nature in their 

 relationship to physiological processes in 

 general will appeal most strongly; while 

 to a third, the chemical dynamics or kinet- 

 ics of physiological processes, the action 



of inorganic salts and their respective ions 

 upon protoplasmic activity, etc., will seem 

 the more promising field of work. In this 

 latter field, we all recognize the great value 

 of the results obtained in the laboratories 

 here at Chicago, with equal recognition of 

 the broad influence which the theories and 

 conclusions drawn therefrom by Loeb, 

 Mathews and others, have had upon the 

 development and progress of this branch 

 of our science. 



Understanding fully the natural tend- 

 ency of chemists and physiologists to dif- 

 fer somewhat in their estimate of the rela- 

 tive value of the different subjects calling 

 for investigation, we may still, I think, 

 readily select for discussion a certain num- 

 ber of problems in biological chemistry 

 which we shall all recognize as being pre- 

 eminently important to-day, and the settle- 

 ment of which would go far toward giving 

 a clearer understanding of many of the 

 functions of the body. Among these prob- 

 lems stands out with startling distinctness 

 the question of the chemical constitution 

 of protein material. To the chemical mind 

 interested in biological matters there is no 

 problem that can overshadow this one in 

 importance. As the basis of cell proto- 

 plasm of all kinds, protein stands forth as 

 the one substance or class of substances 

 absolutely essential for life. It is the 

 chemical nucleus or pivot around which 

 revolves a multitude of reactions character- 

 istic of biological phenomena. In all the 

 metabolic processes of animals and plants 

 protein in some form plays a conspicuous 

 part, and its many katabolic or decomposi- 

 tion products testify both to its com- 

 plexity of structure and to the great di- 

 versity of reactions that may accompany 

 its disintegration. 



Nowhere is there to be found a better 

 illustration of the physiological power 

 which may reside in a certain definite 

 grouping of elements than is seen in the 



