. The Biological bulletin. Biology; Zoology; Marine biology. Figure 13. Reversals induced by locally heating the inactive pacemaker or cooling the active pacemaker. The bath temperature vi^as maintained at 15° C. Localized warming (downward brackets) or cooling (upward brackets) was accomplished by running hot or cold water through a thermode positioned close to the pacemaker regions. Position of ink writer pen was changed at (c). Record 1. Reversals due to raising the temperature of the inactive pacemaker region by about 5° C. Record 2. Reversal due to cooling of the active pacemaker by 5° C.
. The Biological bulletin. Biology; Zoology; Marine biology. Figure 13. Reversals induced by locally heating the inactive pacemaker or cooling the active pacemaker. The bath temperature vi^as maintained at 15° C. Localized warming (downward brackets) or cooling (upward brackets) was accomplished by running hot or cold water through a thermode positioned close to the pacemaker regions. Position of ink writer pen was changed at (c). Record 1. Reversals due to raising the temperature of the inactive pacemaker region by about 5° C. Record 2. Reversal due to cooling of the active pacemaker by 5° C. isolated hearts, the pacemaker maintained at the greater temperature continuously paced the heart up to 8 hours. In other hearts, the heated pacemaker either stopped or missed beats after 30 minutes to four hours at which time the formerly quiescent pacemaker became active, but the duration of activity was short since the heated pacemaker always started again so that a short competition reversal ensued. In Ascidia, small Chelyosoma and Corella hearts, the reversal-periods were usually under three minutes but pacemakers could be kept active for over an hour by local Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-; Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report; HighWire Press. Lancaster, Pa. [etc. ] : Lancaster Press, inc. [etc. ]
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