22 PHYSIOLOGY AND HEALTH. 



32. The gastric juice is prepared within the walls of the 

 stomach, and thrown out from its mucous or lining mem- 

 brane in a manner similar to that in which the saliva is 

 thrown out from the glands of the mouth, or the sweat is 

 poured out from the skin. It exerts a powerful action on 

 all proper and natural sorts of food meat, bread, vegeta- 

 bles, fruits, mixed in every variety of combination, and 

 cooked in all kinds of ways. It dissolves certain important 

 elements which form a constituent part of nearly all our 

 food. By this process it helps to reduce the finely-divided 

 mass to a condition which is fitting for the absorption of its 

 nutritious portions into the blood. 



33. These elements, which are thus acted upon by the 

 gastric juice, are called the albuminoid portions of the food, 

 because they resemble the albumen or white of an egg in 

 their properties and relations. These elements are combined, 

 in different forms and proportions, with other constituents of 

 the food, such as the starch, sugar, oily matters, salts, &c., 

 and are among the most constant and nutritious of its ele- 

 ments. Thus, in form of albumen cindjibrine, they constitute 

 the basis of all our meats ; as cascine they enter into milk ; as 

 gluten they exist in large proportions in the grains wheat, 

 corn,&,c. ; while as legumine they are found in peas and beans. 



34. It has been ever easy to learn the structure of the 

 stomach, and the arrangement of its coats, and its relation 

 to other organs. But the method by which these operate, 

 and the processes of digestion, have been left to inference or 

 conjecture, until within a few years. Men could watch their 

 own sensations of comfort or pain, and notice the results 

 of strengthening and weakness from eating ; but they could 

 not see the steps, and had no means of knowing, for a cer- 

 tainty, what was going on in the stomach, until an opportu- 

 nity was offered to Dr. Beaumont, of the United States army, 

 in the year 1822, and afterwards. A young soldier, Alexis St. 

 Martin, received a gun-shot wound in his left side, which laid 

 his stomach open. The aperture did not close up, but left an 

 opening, through which food could be put in and taken out, 

 and the whole process of digestion observed. A flap of skin 



