152 DIGESTION IN THE LIVING STOMACH. [BOOK II. 



grasps, and kneads and rotates a perfectly contrived arrangement 

 for continually mixing the food to be dissolved with the solvent juice. 

 The stomach is a receptacle, too, in which absorption is continually 

 going on, of water holding certain substances in solution, and secretion 

 of the pepsin and acid needed to carry on the digestive process ; a 

 receptacle from which at a certain period of digestion, the more 

 finely subdivided matter is gradually drained away, through the 

 pyloric orifice, leaving the grosser masses to be further subjected to 

 the combined influence of mechanical movements and the solvent 

 action of gastric juice. 



General Sketch of Digestion in the Living Stomach. 



When food is introduced into the living stomach, the mucous 

 membrane which was previously pallid becomes injected: droplets of 

 liquid commence to exude from the open mouths of the gastric glands, 

 and uniting, form a stream of gastric juice. At the same time the 

 organ contracts around the mass which it contains, and complex 

 movements occur which cause "not only a constant disturbance or 

 churning of the contents of the organ, but compel them, at the same 

 time, to revolve around the interior from point to point and from one 

 extremity to the other 1 ." In order to form a proper conception of the 

 stomach during digestion we must not think of it as a flaccid sac of 

 definite form, such as it appears after death, but as varying in size 

 and also in shape as its walls grasp tightly the mass which it con- 

 tains, and as waves of contraction slowly pass over it, forcing the mass 

 round and round in various planes. 



"When food first enters the stomach the movements are feeble and 

 slight, but as digestion goes on they become more and more vigorous, 

 giving rise to a sort of churning within the stomach, the food travelling 

 from the cardiac orifice along the greater curvature to the pylorus, and 

 returning by the lesser curvature, while at the same time subsidiary 

 currents tend to carry the food which has been passing close to the mucous 

 membrane towards the middle of the stomach, and vice versa 2 ." 



"While these revolutions of the contents of the stomach are progressing, 

 the trituration or agitation is also going on. There is a perfect admixture 

 of the whole ingesta, during the period of alimentation and chymification. 

 There is nothing of the distinct lines of separation between old and new 

 food, and peculiar central or peripheral situation of crude, as distinguished 

 from chymified aliment, said to have been observed by Philip, Magendie, 

 and others in their experiments on dogs and rabbits, to be seen in the 

 human stomach; at least in that of the subject of these experiments. The 

 whole contents of the stomach, until chymification be nearly complete, 

 exhibit a heterogeneous mass of solids and fluids; hard and soft; coarse 



1 Beaumont, Experiments and Observations on the Gastric Juice. Edinburgh 

 Edition, 1838, p. 101. 



2 Foster, Physiology, 3rd ed. (1879), p. 270. 



