Principles of human physiology / by William B. Carpenter.

  • Carpenter, William Benjamin, 1813-1885.
Date:
1864
Catalogue details

Licence: Public Domain Mark

Credit: Principles of human physiology / by William B. Carpenter. Source: Wellcome Collection.

    99/1026 (page 65)
    it enters the cardia, turns to the left, passes the aperture, descends into the splenic extremity, and follows the great curvature towards the pyloric end. It then returns, in the course of the smaller curvature (or as Dr. Brinton supposes, through the axis of the stomach), and makes its appear- ance again at the aperture in its descent into the great curvature, to per- ^ form similar revolutions. These revolutions are completed in from one to three minutes. They are probably induced, in a great measure, by the circular or transverse muscles of the stomach. They are slower at first, than after chymification has considerably advanced; at which time also there is an increased impulse towards the pylorus. It is probable that, from the very commencement of chymification, until the organ be- comes empty, portions of chyme are continually passing into the duode- num ; for the bulk of the alimentary mass progressively diminishes, and this the more rapidly as the process is nearer its completion. The ac- celerated expulsion appears to be effected by a peculiar action of the transverse muscles; and especially of that portion of them, which surrounds the stomach at about four inches from its pyloric extremity. This band is so forcibly contracted in the latter part of the digestive process, that it almost separates the two portions of the stomach into a sort of hour-glass form; and Dr. Beaumont states that, when he attempted to introduce a long thermometer-tube into the pyloric portion of the stomach, the bulb was at first gently resisted, then allowed to pass, and then grasped by the muscular parietes beyond, so as to be drawn-in: whence it appears that the contraction has for its object, to resist the passage of solid bodies into the pyloric extremity of the stomach, at this stage of digestion, whilst the matter w^hich has been reduced to the fluid form is pumped-away (as it were) by the action of that portion of the viscus. These peculiar motions continue, until the stomach is perfectly empty, and not a particle of food or of chyme remains; and when they are nearly brought to a close, the contraction of the pyloric orifice also gives-way, to an extent sufificient to allow not only the undigested residue of the food, but also large solid bodies that may have been swallowed (such as coins and the like), to pass into the intestinal canal. I 72. With regard to the degree in which these movements of the Stomach, whose share in the Digestive operation is so important, are de- pendent upon the Spinal cord, and are consequently of a ' reflex' nature, it is difiScult to speak with certainty, owing to the contradictory results obtained by different experimenters. These contradictions, however, seem partly due to a diversity in the nature of the animals experimented-on, and partly to a difiference in the stage of the digestive process at which the observations were made. It seems to be well established by the researches of Reid, Valentin, and others,^ that distinct movements may be excited in the stomach of the Rabbit, if distended with food, by irritat- I ing the Pneumogastric soon after the death of the animal; these move- I ments appear to commence from the cardiac orifice, and then to spread j * See Dr. Reid's Physiological, Anatomical, and Pathological Researches, chap. v. ; Valentin, De Functionibus Nervorum Cerebralium, &c., chap, xi. ; also Longet, Anat. et Physiol, du Systeme Nerveux, torn. i. p. 323 ; and Physiologic, vol. i. p. 234, 1861 ; and Bischoff in Miiller's Archiv, 1843. Pincus, *'Exp. de vi Nervi Vagi, I Wratislaw, 1856 ; Hartung, Ueber die Nervi Vagi, Giessen, 1858 ; Schiff, ''Physio- I logic, 1859, p. 420 ; Bernard, Med. Times and Glaz., 1860, vol. ii. p. 1 ; Ravitsch, , ^'Mtiller's Archiv, 1861, p. 779. I