Mercer's company lectures on recent advances in the physiology of digestion (1906) (14597131540)

Identifier: cu31924000041669 (find matches)
Title: Mercer's company lectures on recent advances in the physiology of digestion
Year: 1906 (1900s)
Authors: Starling, Ernest Henry, 1866-1927
Subjects: Digestion
Publisher: London, Archibald Constable and Co.
Contributing Library: Cornell University Library
Digitizing Sponsor: MSN

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ion of acid into the small intestine, is shown bythe fact that its distribution in the gut exactly correspondswith Wertheimers results. Thus, whereas extraction of themucous membrane of the duodenum yields a very strongsolution of secretin, a similar acid extract or decoction of thelower two feet of ileum yields a solution which has no influenceon the pancreas. We have here an example of a type of mechanism whichprobably plays an important part in the correlation of activitiesof many organs of the body. In the normal life of the higheranimals, which must be considered as a continuous series of PANCKEATIC SECRETION. 89 reactions to changes in the environment, ending only with thedeath of the animal, those reactions, which are carried outthrough the intermediation of the nervous system, play sucha preponderant part, that we have almost forgotten thepossibility of other means of co-adaptation among the differentorgans of the body.Yet, in the lowest organisms, before the appearance of any
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Fig. 9.—Effect of secretin prepared by the acuon of dilute acid onintestinal mucous membrane which had been extracted with hot absolutealcohol. The effect on the pancreas is the same as with the extract offresh mucous membrane, but the alcohol has removed the substanceresponsible for the fall of blood pressure, which generally follows theinjection of fresh extracts. central nervous system, it is by chemical means that anyco-ordination of function is determined, either among thedifferent organisms of a colony, or among the various cellsmaking up a multicellular organism such as the sponge. Inthis case the mechanism, which determines the movement ofphagocytic cells towards an irritant, the chase of food, theescape from noxious environment, or the approach of sexual 90 TIIE PHYSIOLOGY OF DIGESTION. cells, has been given the name of chemiotaxis. Since theapplication of these chemical stimuli depends on their diffusionthrough the medium bathing the cells, the process is neces-sarily a ve

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