THE PHYSIOLOGICAL AND 

 PATHOLOGICAL CHEMISTRY 

 OF METABOLISM " 



CHAPTER I 



INTRODUCTION TO THE STUDY OF METABOLISM. 

 PROTEIN DIGESTION IN THE STOMACH 



INTRODUCTORY 



EVEBY one knows full well with what feelings of joy and 

 satisfaction the mountain climber after long and tiresome 

 trudging at last reaches some hoped-for height and views 

 the silent space around and about him. If fortune smile 

 and the blue dome arch out before him without a cloud to 

 its farthest reaches, how easy it is for the wanderer to lose 

 himself in contemplation of the unending, shining distances, 

 and to allow to dawn within him a shadowy presentment of 

 the eternal and infinite. But days of such good luck are rare ; 

 much more often the traveller on the heights must be satisfied 

 if spiteful mists do not completely cheat him of the reward 

 of his labor, and if some little part of the majesty he had 

 hoped to look upon remain unfilched from view. It may well 

 be that only one small part in all that mountain world stands 

 forth in sharply outlined configuration to satisfy his gaze. 

 All other regions seem covered by a vast cloak of vapor, with 

 only the uncertain shadows of grosser outlines shown. In 

 the far distances lie thick banks of clouds and rolling, steam- 

 ing shapes of mist, sweeping out from the clefts, clinging in 

 the valleys, and refusing to permit even a guess of what lies 

 buried behind them. 



So, too, with us, after long and tiresome wandering, this 

 mountain pass is attained; 1 from which we may hope to 

 advance some little way, perchance, into the broad, mys- 

 terious domain of the physiology of metabolism. In allur- 



1 Referring to the series of lectures preceding the present text, in the 

 volume entitled " Chemistry of the Tissues," in the original German edition. 



1 



