Experimental physiology / by Sir Edward Sharpey-Schafer.

  • Edward Albert Sharpey-Schäfer
Date:
1934
Catalogue details

Licence: In copyright

Credit: Experimental physiology / by Sir Edward Sharpey-Schafer. Source: Wellcome Collection.

    30/184 page 18
    shunting. This permits both the break and the make self-induced e.m.f. to be effective, and tends to equalise the make and break stimuli. It is obvious that tetanic stimuli applied to a tissue by means of the arrangement shown in Fig. 20 are bound to produce a certain amount of electrolysis of the tissue, since the potential between the electrodes at break is always very much greater than at make, with the result that the make current, while flowing in the opposite direction to the break, is not sufficient to reverse the polarisation occasioned by the break current. With the Helmholtz arrangement, on the other hand, the make and break shocks being almost equal tend to neutralise the polarising effects of each other, and thus damage to the stimulated tissue is reduced to a minimum. The Helmholtz arrangement should always be employed for tetanic stimulation.
    No text description is available for this image
    No text description is available for this image
    No text description is available for this image