The caudal heart of the eel ... / by Thomas Wharton Jones.

  • Jones, Thomas Wharton, 1808-1891.
Date:
[1867?]
Catalogue details

Licence: Public Domain Mark

Credit: The caudal heart of the eel ... / by Thomas Wharton Jones. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    4/16 (page 676)
    Being laid on the slide with the tail in proper position, the animal was fixed by tying a string loosely round the slide and its body where enveloped in the rag. The part of the tail to be examined was covered with water and a thin plate of glass. Matters being thus arranged and the microscope adjusted, rapid pulsations are imme- diately detected, on directing the eye to the region of the extreme end of the vertebral column—abdominal side *. No very well-defined heart-like organ is observable at first sight, but the pulsations seem as if in the tissue of the part generally. The skin and substance of the tail sur- rounding the heart are drawn somewhat together at each systole, and fall back into their previous state at each diastole. From this it may be inferred that the heart does not lie free in a special cavity, nor even in loose cellular tissue, but that it is imbedded in the substance of the tail. Dissection of the tail of a large eel shows that the heart is connected with the adjacent bonesf. The great vein of the tail J is formed by the junction of two trunks, a larger and a smaller §. The larger trunk receives the venous radicles returning the blood from the terminal and abdominal parts of the caudal fin. The smaller trunk receives the venous radicles returning the blood from the dorsal part. It is into this smaller trunk, near its junction with the larger, that the caudal heart opens. The great artery of the tail || runs close alongside the vein, and is smaller than it, and somewhat tortuous. It gives off branches to the abdominal and dorsal parts of the caudal fin, whilst the continuation of it subdivides into the small ramifications distributed to the terminal part. This continuation of the artery and the larger trunk of the great caudal vein diverge from each other in their course towards the end of the tail, and then, after having become small by the giving off of branches, approach curvingly and cross each other at the place where the spine ends and the terminal part of the caudal fin commences. The elongated space bounded by the artery and vein thus diverging from and again approaching each other, is that in which the lymphatic heart is situated^]. Description and explanation of the phenomena attending the propulsion of the lymph from the caudal heart into the caudal vein. At the opening of the caudal heart into the vein there is a valve which prevents regurgitation of the lymph back from the vein into the heart; but, owing to the thick- * Plate XXXV. figs. 1 & 2, E. t This point in the anatomy of the caudal heart is described in detail in Part III. of my paper entitled, “ Microscopical characters of the rhythmically contractile muscular coat of the veins of the Bat’s wing, of the lymphatic hearts of the Frog, and of the caudal heart of the Eel.” t Plate XXXV. figs. 1 & 2, B. § Plate XXXV. figs. 1 & 2, C, D. || Plate XXXV. fig. 1, A. f Plate XXXV. fig. 1, E.