220 DIGESTION. 



tity of blood; the gastric glands commence secreting actively, 

 and an acid fluid is poured out in minute drops, which gradu- 

 ally run together and flow down the walls of the stomach, or 

 soak into the substances introduced. The quantity of this fluid 

 secreted daily has been variously estimated ; but the average 

 for a healthy adult has been assumed to range from ten to 

 twenty pints in the twenty-four hours (Brinton). 



The first accurate analysis of the gastric fluid was made by 

 Dr. Prout; but it does not appear that it was collected in any 

 large quantity, or pure and separate from food, until the time 

 when Dr. Beaumont was enabled, by a fortunate circumstance, 

 to obtain it from the stomach of a man named St. Martin, in 

 whom there existed, as the result of a gunshot wound, an open- 

 ing leading directly into the stomach, near the upper extremity 

 of the great curvature, and three inches from the cardiac orifice. 

 The external opening was situate two inches below the left 

 mamma, in a line drawn from that part to the spine of the 

 left ilium. The borders of the opening into the stomach, which 

 was of considerable size, had united, in healing, with the mar- 

 gins of the external wound, but the cavity of the stomach was 

 at last separated from the exterior by a fold of mucous mem- 

 brane, which projected from the upper and back part of the 

 opening, and closed it like a valve, but could be pushed back 

 with the finger. The introduction of any mechanical irritant, 

 such as the bulb of a thermometer, into the stomach, excited 

 at once the secretion of gastric fluid. This could be drawn off 

 with a caoutchouc tube, and could often be obtained to the 

 extent of nearly an ounce. The introduction of alimentary 

 substances caused a much more rapid and abundant secretion 

 of pure gastric fluid than the presence of other mechanical 

 irritants did. No increase of temperature could be detected 

 during the most active secretion ; the thermometer introduced 

 into the stomach always stood at 100 Fahr., except during 

 muscular exertion, when the temperature of the stomach, like 

 that of other parts of the body, rose one or two degrees higher. 



M. Blondlot, and subsequently M. Bernard, and since then, 

 several others, by maintaining fistulous openings into the 

 stomachs of dogs, have confirmed most of the facts discovered 

 by Dr. Beaumont. And the man St. Martin has frequently 

 submitted to renewed experiments on his stomach, by various 

 physiologists. From all these observations it appears, that 

 pepper, salt, and other soluble stimulants, excite a more rapid 

 discharge of gastric fluid than mechanical irritation does ; so 

 do alkalies generally, but acids have a contrary effect. When 

 mechanical irritation is carried beyond certain limits so as to 

 produce pain, the secretion, instead of being more abundant, 



