312 



STOMACH AND INTESTINE. 



stomach.* This condition remains for some 

 instants. And when the alimentary bolus has 

 in this manner been impelled into the organ, 

 it excites muscular movements. 



The exact condition of the cardia during 

 stomach digestion is scarcely known. It is 

 obvious that the force with which it is shut 

 must be effectively superior to the pressure 

 exerted on the contents of the organ by 

 the gastric contractions. Still we are igno- 

 rant how much of this force is due to the 

 contraction of the lower cesophageal fibres, 

 and how much to the shape, position, or 

 structure of the stomach itself. Indeed, 

 one cannot help conjecturing, that the de- 

 cussation of the transverse and oblique fibres 

 of the organ around the insertion of the 

 oesophagus, might render their contractions 

 a material assistance to the obliteration of 

 the lower part of this tube. From the ob- 

 servations of Magendie-j-, it would seem that, 

 during digestion, the cardia contracts tightly 

 around a finger introduced from the stomach ; 

 and that the distention of the gastric cavity 

 appears to regulate the intensity and duration 

 of this closure, so much so, that pressure 

 by the hands, or by the diaphragm during 

 inspiration, produces an increase of contrac- 

 tion. J And the disappearance of this efficient 

 closure in the dead, or even in the exhausted;) 

 animal, suffices to show, what indeed we 

 might gather from its great energy, that 

 it is not due to mere passive contractility. 

 Hence, on the whole, it appears preferable to 

 regard the cardiac orifice as closed by an 

 active muscular contraction, which is itself 

 excited by the direct stimulus of the food 

 that distends the stomach. 



Perhaps there are few more difficult parts 

 of our inquiry than that which relates to the 

 precise nature of those movements which are 

 executed by the stomach, and impressed upon 

 the food, during its sojourn in this cavity. For 

 the vivisection of animals has given few results ; 

 and even had they been more marked, they 

 would scarcely have been trustworthy. The 

 human corpse is generally diseased, or, if not, 

 the interval after death which precedes an ex- 

 amination of its abdominal viscera is suffi- 

 cient to remove all appearances of activity. 



* Beaumont (Experiments and Observations on 

 the Gastric Juice. Combe's Edition. 1808), pp. 62, 

 63., and elsewhere. Valentin, Lehrbuch der Phy- 

 siologie, Band i. p. 269. Magendie, Precis e'le'- 

 mentaire de Physiologic : Quatrieme edition, vol. ii. 

 p. 70. 



f Op. cit. pp. 81, 82. 



j Magendie (foe. cit.) and Mueller (Handbuch 

 der Physiologic, Bd. i. p. 412) state tliat an alter- 

 nating and rhythmical movement of the oesophagus 

 accompanies digestion. It is independent of deglu- 

 tition. The contraction of the tube coincides with 

 the period of inspiration ; and, vice versa, its relaxa- 

 tion with expiration. But such results of vivisection 

 cannot be safely regarded as the ordinary pheno- 

 mena of the healthy body. As to how far the cardia 

 is necessarily closed by the diaphragm in the act of 

 inspiration, I may refer to the note to p. 309. : to 

 which I will only add, that any one may satis- 

 factorily disprove its real occlusion by swallowing a 

 bolus of food at this period. 



Magendie, foe. cit. 



And, finally, the results obtained from newly- 

 killed animals on the one hand, and from Dr. 

 Beaumont's valuable case on the other, are 

 apparently so indefinite, or even so conflicting, 

 that most physiologists seem content to leave 

 the question in abeyance, until more numerous 

 or more comparable facts afford better grounds 

 for a decision. 



A careful comparison of such results has, 

 however, led the author to adopt the follow- 

 ing views *, which appear to unite in one 

 theory most of the facts hitherto ascertained 

 respecting the muscular action of the healthy 

 digesting stomach. 



1. In the fasting state the empty stomach 

 offers no movement whatever. This fact, which 

 is asserted by Dr. Beaumontf , from his obser- 

 vations on the living human subject, may be 

 readily verified by laying open the bellies of the 

 domestic mammalia immediately after death. 

 Some very slight and gradual changes in the 

 shape of the organ, which I have once or twice 

 noticed, form no valid exception to such a 

 rule. This agreement in the above two classes 

 of results is not only interesting in itself, but 

 entitles us to lay somewhat more stress on 

 that which follows. And it is especially useful, 

 in that it frees us from the apprehension that 

 any contractions which we may observe can 

 be caused, or even greatly modified, by the 

 air J to which the dead animal's stomach is ex- 

 posed. 



2. At the commencement of digestion, or 

 immediately after the deglutition of food, the 

 movement of the stomach offers three varieties. 



. In some animals, a large quantity of food is 

 often hastily swallowed, after scarcely any sub- 

 division, far less mastication. Under these 

 circumstances, the stomach is found closely 

 contracted around its hard contents, some- 

 times even adapting its shape to that of these 

 unyielding masses. And, as might be ex- 

 pected, no motion is discernible. 



b. Dr. Beaumont narrates the opposite ef- 

 fect of a very small quantity of liquid food in 

 the human subject. It excites a vermicular 

 action, a gentle contraction or grasping motion 

 of the stomach, so that the wrinkles of the 



* These will be found in an Essay which, writ- 

 ten in 1847, was published in the " Medical Gazette " 

 for 1849. 



f Beaumont, at p. 105. expressly; at pp. 23. 57., 

 by implication. 



J Though, by the bye, as this would chiefly cause 

 irregular motions, it would rather oppose, than pro- 

 duce, any uniform and constant movement. The 

 effect of air on the intestine is alluded to hereafter. 



This condition, which is frequent in the domestic 

 Carnivora, appears to be usual in the Rabbit, in whom 

 it is often kept up by the comparatively unyielding 

 nature of the food. In such a case the contents of 

 the stomach are dissolved, as it were, from without 

 inwards, in successive strata; which are slowly and 

 constantly stripped off by the muscular action, and 

 squeezed through the pylorus. In all these instances 

 I have found the movements of the organ much less 

 marked than where the food was present in a smaller 

 quantity and a state of greater subdivision. And 

 in the Rabbit, both the stomach and intestine appear 

 to be unusually sluggish; as shown by the feeble 

 movements of the former during digestion, and of 

 the latter under the magneto -electric stimulus. 



