Therapeutics of the circulation / by Sir Lauder Brunton.

  • Lauder Brunton
Date:
1914
Catalogue details

Licence: Public Domain Mark

Credit: Therapeutics of the circulation / by Sir Lauder Brunton. Source: Wellcome Collection.

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    rhythmical contraction apart from any ganglia, yet it is from the ganglia that the stimuli to rhythmical contraction usually proceed. In regard to those parts of the heart from which the stimuli to contraction proceed, it might be better to speak of conversion rather than of origination of stimuli, because they probably do not generate a new stimulus, but only convert a constant stimulus into a rhythmical one, just as the ganglion-free apex responds to a constant mechanical or chemical stimulus by rhythmic contractions. The difference between the apex which is without, and the sinus which contains ganglia, is not so much one of kind as of degree. When Stannius’s ligatures are applied under oil, so that the heart is not exposed to the stimulus of the air, the ventricle only contracts when Bidder’s ganglia are stimu¬ lated by the application or removal of the ligature.16 Conduction of Stimuli in the Heart.—Accord¬ ing to the neurogenic theory, the stimuli are transmitted from the venous sinus to the auricle, and from the auricle to the ventricle, by nerve fibres ; but the quotation I have already given from Tawara (p. 27) shows that those who hold the myogenic theory entirely deny this trans¬ mission by nerve fibres, and assert that it occurs only through the block fibres already mentioned, and through the muscular fibres of the heart itself.17 Heart-block. Gaskell’s Experiments.— It was discovered by Gaskell that when the frog’s heart is placed in a clamp, the jaws of which lie
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