The nature of gastric peristalsis / by W.B. Cannon.

  • Walter Bradford Cannon
Date:
[1911?]
Catalogue details

Licence: Public Domain Mark

Credit: The nature of gastric peristalsis / by W.B. Cannon. Source: Wellcome Collection.

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    also the same factors are operative, as can be demonstrated in various ways. . 1. If a cat which has not recently taken food is etherized, its spinal cord destroyed below the brachial region, and its stomach exposed by opening the abdomen under warm normal salt solution, the stomach may be found moderately contracted (z.e., in a tonic state), or relaxed and flaccid. In either case the organ will be inactive. Tf now fluid is introduced into the stomach, the effect will differ ac- cording to the status of the muscle. In the contracted stomach the introduced fluid encounters resistance, the pressure applied causes distention of the gastric walls, and peristaltic waves are at once started. In the relaxed stomach, on the other hand, the introduction of even large amounts of fluid usually has no effect — the walls simply retreat before the increasing content. These observations show that tonus (7. e., a shortened state) may be present in muscle without observable activity, that extension of atonic muscle does not produce activity, but that extension of tonic muscle results in the characteristic rhythm. That distention of the stomach is a stimulus to its contractions has long been observed. Spallanzani noted that when a hen, starved for a day, was given nuts to-eat, no movements of the stomach oc- curred so long as the organ contained only a few nuts, but that activ- ity started promptly as soon as the stomach began to be full.? Hof- meister and Schiitz have recorded the appearance of powerful con- tractions of the excised stomach of the dog when it was inflated with air and carbon dioxide. And Ducceschi found that distention of the gastric walls caused the appearance of rhythmic contractions, and that within limits the amplitude of these contractions increased pro- gressively as distention increased.’ All these observations are in accord with results obtained by experimentally stretching the smooth muscle of various other hollow viscera. In none of these instances, however, so far as I have been able to learn, was any attention paid 5 SPALLANZANI: Versuche iiber das Verdauungs-Geschiafte, translated from the Italian, Leipzig, 1785, p. 30. 6 HoFMEISTER and Scutz: Archiv fiir experimentelle Pathologie und Pharma- kologie, 1885, xx, p. 15. ” Duccescui: Archivio per le scienze mediche, 1897, xxi, pp. 146, 140.
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