On the electrical phenomena accompanying secretion in the skin of the frog / by W.M. Bayliss and J. Rose Bradford.

  • Bayliss, William Maddock, Sir, 1860-1924.
Date:
[1885?]
Catalogue details

Licence: Public Domain Mark

Credit: On the electrical phenomena accompanying secretion in the skin of the frog / by W.M. Bayliss and J. Rose Bradford. 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.

    10/16 (page 224)
    The discrepancy between the results obtained by Hermann and Engelmann is thus satisfactorily cleared up, if it be the case that Engelmann experimented in the early spring months, and Hermann later on in the year. Photographs of the variation with the capillary electrometer have been obtained by us; they only show that the gal- vanometer gives correct indications of the relative strengths of the phases and does not distort the “Yorschlag” as it does in the case of Dionaea. Reflex Excitation. Contrary to expectation, we found it very difficult to obtain distinct effects on reflex excitation, and so our attention was not much directed to this part of the subject; one or two experiments however afforded rather interesting results. The two legs of a frog were led off in the usual way, the sciatic nerve on the left side prepared in the thigh divided, the central end being stimulated a deflection of + 50 was observed, i.e. a small positive variation; on now exciting the cord in the usual way a deflection of — 350 was seen, i.e. a negative variation. No result was obtained by dipping the toes into sulphuric acid l°/0. On another occasion a negative variation was obtained by stimulating electrically the toes of that leg of which the skin was being observed; the variation on cord stimulation was also negative. Hypotheses. It will make the subsequent portion of this paper more easily understood if we proceed now to discuss shortly the various hypotheses that have been suggested to account for the facts which we have mentioned above. Hermann in his first paper suggests that the two directions of the secretory variation are due to the two kinds of glands, which are known to be present in the frog’s skin—thanks to the investigations of Le)Tdig, Eberth, and Engelmann; the positive variation having its origin in the small, regularly distributed, mucous glands, the negative variation in the larger, irregularly distributed, granular glands. In the middle portion of the skin of the back of R. esculenta the former are almost exclusively present, whilst in the other parts of the skin the latter are abundantly scattered. Since the secretion of the back is according to Hermann alkaline, while blue or neutral tinted litmus paper placed