On the inervation of the heart, with especial reference to the heart of the tortoise.

  • Gaskell, Walter Holbrook, 1847-1914.
Date:
1883
Catalogue details

Licence: Public Domain Mark

Credit: On the inervation of the heart, with especial reference to the heart of the tortoise. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    k,1*S>si^ and tL 'otHave„f Wa3to ;^‘S; /T^ti»'«,«*-aH. le JllDetion wall alone, leaving the the means of communication between converse]/ of removal of tie bulged tion wall between tie two auridei i of the opposite effects of these two INNERVATION OF THE HEART. 75 always the same, although the band of tissue which was left intact in the first case along which the contractions might travel to reach the ventricle, was many times broader than the final bridge of the reticulated muscular tissue in the second case; although, in addition to the greater breadth of the strip, the nerve communications ganglia and all, between the sinus and the ventricle were intact in the first experiment while in the second nothing was left but a narrow muscular bridge as the means of communication between sinus and ventricle; yet the sequence was absolutely prevented in the former case, absolutely unaffected in the latter. We see then without doubt not only that the sequence depends on the passage of a contraction over the bulged portion of the auricles to the upper portion of the auriculo-ventricular junction ring, but also the conduction of the contraction is less easy along the muscular tissue of the junction wall between the two auricles than along the reticulated muscular network of the bulged portion of the auricles. I do not desire to assert that a contraction wave can never pass along the inter- auricular junction wall and so to the ventricle, for I have seen in one or two cases a slight and partial repair of the sequence some time after the tortoises were taken and their hearts junction wall uppermost In each case i*1“vt1*2 e junction wall ^ ^ted <*>u^?b*<***, and ^ fa first & ^odlj fftction4 ^ter extend and fet In1* ,t. con*1*0.. tjcgueo1hr the ***$&. tnP , s#“° * operation when the junction wall alone was left; I only assert that in all cases the sequence is maintained with immensely greater ease when only a small bridge of the reticulated muscular tissue is left, over which the contraction wave can travel, than when the whole of the junction wall is left intact. Finally, the assertion based upon the experiments of Eckhard and Marchand, that the auriculo-ventricular ganglia are essential for the due sequence of the ventricular upon the auricular contractions in the frog, must be examined into and its truth or falsity proved. The fibres of the auricles in the frog pass into a well defined ring of circularly arranged muscle fibres at the junction between the auricles and ventricle of the same nature as already described for the tortoise. The diameter of this ring is naturally as small as the orifice between the auricles and the ventricle, so that in such an operation as the removal of the auriculo-ventricular ganglia it is easy to cut away or damage this muscular ring, even while apparently leaving the connections between auricles and ventricle intact. I have however succeeded in removing the two ganglia without injury to this ring as follows. I first opened and removed a portion of the apex of one auricle, washed out and at the same time slightly distended the heart with a jet of normal saline solu- tion, so as to bring the septum into view: I then seized the septum with a pair of fine forceps and gently drew it forward, until the two white PH. IV. 7 T