250 



Food and its Digestion. 



tion, we can only learn it by observation and experi- 

 ment. 



A necessary condition in estimating the value of any 

 substance as an article of food, is its digestibility. A vege- 

 table or an animal tissue may contain an abundance of 

 albuminoid or starchy matter, and still at the same time 

 be of such unyielding consistency, as to be insoluble in 

 the digestive fluids, and therefore prove useless as an 

 article of food. 



Consequently, any process which softens or disinte- 

 grates a hard alimentary substance, renders it more di- 

 gestible, and increases its value as an article of food. 

 The preparation of food by cooking therefore, is a very 

 necessary process, though doubtless in its refinement, too 

 often is its good perverted. Two objects are accomplished 

 by cooking — first the food is softened and disintegrated, 

 so that its particles may be more fully and effectually 

 acted upon by the gastric juice in the stomach ; and again, 

 by the process of cooking, generally an agreeable flavour 

 is imparted to the food, which flavour stimulates the 

 gastric follicles to pour out an increased flow of their 

 digestive fluid. 



By a chemical analysis of food, we gain much positive 

 information as regards the nutritive qualities of the differ- 

 ent kinds which we use, and by our advances in physio- 

 logical knowledge, we have learned much in reference to 

 the adaptability of food to the different requirements of 

 the system, and yet for much valuable information we 

 have had to rely upon fortunate experiments, such as Dr. 

 Beaumont, of the United States' army, performed upon 

 Alexis St. Martin, a Canadian, who was wounded by the 

 accidental discharge of his gun at Michilimackinac, 

 Michigan, in 1822, whilst Dr. Beaumont was stationed 

 there, and under whose charge St. Martin was placed. 

 Though the contents of the gun made a perforation 

 through the walls of the stomach, the man survived, but 

 this perforation was never closed, consequently through it 



