18 PRINCIPLES- OF BIOCHEMISTRY 



culture and the industries, that almost everywhere the study of bio- 

 chemistry ranks with that of anatomy, physiology and pathology as 

 one of the studies fundamental to the understanding of medical science, 

 or with botany, plant-physiology and bacteriology as one of the studies 

 fundamental to the understanding of agriculture. 



It must not be supposed, however, that the withdrawal of biochem- 

 istry from the parent-subject has left physiology any the poorer. 

 Physiology has not been left merely with a residuum of undigested 

 material, ultimately to be absorbed by the biological chemist. On 

 the contrary, with the development of biochemistry, physiology has 

 developed too and that to an extent unimagined by its founders. A 

 few generations ago, physiology was a little-considered fragment of the 

 study of anatomy, just as, one generation ago, biochemistry was a 

 little-considered portion of the study of physiology. The same differ- 

 entiation has separated the teaching of biochemistry from physiology 

 as that which has separated the teaching of chemistry from that 

 of physics. We may regard physiology as consisting for the present 

 of the study of the applications of anatomy and physics to the elucida- 

 tion of life-phenomena, together with the entire study of a residuum of 

 phenomena and processes which are for the present passed by in 

 biochemistry simply because we do not as yet possess any clue whatever 

 to the nature of the chemical processes which underlie them. 



Hence, physiology is destined ultimately and at some as yet far 

 distant date to become the study of the interpretation of life-phenomena 

 by the aid of the principles of anatomy, gross and minute, and physics. 

 Biochemistry is the study of the interpretation of life-phenomena by 

 the aid of the principles and facts of chemistry. Physiology investi- 

 gates the molar and molecular phenomena of life, biochemistry the 

 atomic. 



Of course, this division is arbitrary and unreal, just as the distinc- 

 tion between physics and chemistry is arbitrary and unreal. Nature 

 recognizes no such classification of her phenomena. Physics merges 

 insensibly into chemistry and in like manner physiology merges into 

 biochemistry. An illustration of this fact has been strikingly afforded 

 in recent times by the rapid development of physical chemistry, a 

 whole borderland between physics and chemistry, which has undergone 

 such extensive survey within the last generation as to demand a 

 noteworthy degree of special training on the part of those who would 

 attempt to master it. Even the delineation of this domain has not by 

 any means removed all of the "debatable land," however, that lies 

 between physics and chemistry; witness the recently discovered 

 phenomena of radio-activity, which have opened up yet another field 

 of investigation which is neither physics nor chemistry. And so it is 

 with physiology and biochemistry. There is an indefinite "debatable 

 area" between the two, and many if not most of the problems in either 

 field require the aid of both physiology and biochemistry for their 

 solution. 



