ACTION OF THE STOMACH. 329 



rapidly ; this may be well observed in Horses whilst drinking ; large morsels, 

 however, are frequently some time in making their way down. Each portion 

 of food and drink is included in the contractile walls, which are closely applied 

 to it during the whole of its transit. The gurgling sound which is observed 

 when drink is poured down the throat of a person in articulo mortis, is due to 

 the want of this contraction. The whole of the third stage is completely in- 

 voluntary. The usual peristaltic movements of the oesophagus are reversed 

 in Vomiting ; and this reversion has been observed, even after the separation 

 of the stomach from the oesophagus, as a consequence of the injection of tartar- 

 ized antimony into the veins. At the point where the oesophagus enters the 

 stomach, the cardiac orifice of the latter, there is a sort of sphincter, which 

 is usually closed. This opens when there is a sufficient pressure on it, made 

 by accumulated food ; and afterwards closes, so as to retain the food in the 

 stomach. The opening of the cardia is one of the first acts which take place 

 in vomiting. When the sphincter is paralyzed by division of the pneumo- 

 gastric nerve, the food regurgitates into the oesophagus. 



III. Action of the Stomach. 



438. A remarkable opportunity of ascertaining the condition of the Stomach 

 during Digestion, has lately presented itself, in a case in which a large fistu- 

 lous aperture remained after a wound that laid open the cavity, but in which 

 the general health has been completely recovered, so that the process may be 

 considered as normally performed.* " The inner coat of the stomach, in its 

 natural and healthy state, is of a light or pale pink colour, varying in its hues, 

 according to its full or empty state. It of a soft or velvet-like appearance, and 

 is constantly covered with a very thin, transparent, viscid mucus, lining the 

 whole interior of the organ. By applying aliment or other irritants, to the in- 

 ternal coat of the stomach, and observing the effect through a magnifying glass, 

 innumerable lucid points, and very fine nervous or vascular papillae, can be 

 seen arising from the villous membrane, and protruding through the mucous 

 coat, from which distils a pure, limpid, colourless, slightly viscid fluid. The 

 fluid thus excited is invariably distinctly a,cid. The mucus of the stomach is 

 less fluid, more viscid or albuminous, semi-opaque, sometimes a little saltish, 

 and does not possess the slightest character of acidity. The gastric fluid never 

 appears to be accumulated in the cavity of the stomach while fasting ; and is 

 seldom, if ever, discharged from its proper secerning vessels, except when 

 excited by the natural stimulus of aliment, mechanical irritation of tubes, or 

 other excitants. When aliment is received, the juice is given out in exact pro- 

 portion to its requirements for solution, except when more food has been taken 

 than is necessary for the wants of the system." That the quantity of the 

 Gastric Juice secreted from the walls of the stomach depends rather upon the 

 general requirements of the system, than upon the quantity of food introduced 

 into the digestive cavity, is a principle of the highest practical importance, and 

 cannot be too steadily kept in view in Dietetics. A definite proportion only 

 of aliment can be perfectly digested in a given quantity of the fluid ; the action 

 of which, like that of other chemical operations, ceases after having been exer- 

 cised on a fixed and definite amount of matter. " When the juice has become 



* See the case of Alexis St. Martin, with the observations and experiments of Dr. Beau- 

 mont, republished in this country by Dr. A. Combe. [A very extended examination of 

 the phenomena of gastric digestion has been made by M.Blondlot. The chief subject of 

 experiment was a dog. in which he maintained, without affecting the health, a fismlous 

 opening into the stomach for more than two years. His examinations have furnished 

 many new and important facts, and have confirmed those of Dr. Beaumont made on 

 Alexis St. Martin in nearly every point.] 



28* 



