American journal of physiology . ontractions which lasted avariable, but always a short time.^ In this instance a rhythm was ^ Greene: This journal, 1898, ii, p. 126. 268 D. J. Liiigle. established in a solution of a nonconductor, a fact that directly con-tradicts Loebs idea. I repeated Greenes experiment, using a solu-tion of dextrose equimolecular with a per cent sodium chloridesolution, and got rhythmic contractions in the form of an irregularrhythm lasting about an hour. In this preparation there was an evi-dent tendency for the beats to appear in groups of two to eight beatswith short
American journal of physiology . ontractions which lasted avariable, but always a short time.^ In this instance a rhythm was ^ Greene: This journal, 1898, ii, p. 126. 268 D. J. Liiigle. established in a solution of a nonconductor, a fact that directly con-tradicts Loebs idea. I repeated Greenes experiment, using a solu-tion of dextrose equimolecular with a per cent sodium chloridesolution, and got rhythmic contractions in the form of an irregularrhythm lasting about an hour. In this preparation there was an evi-dent tendency for the beats to appear in groups of two to eight beatswith short pauses between the groups. (See Fig. i.) The dextrosesolution used was made from the ordinary so-called granular chemi-cally pure dextrose. When it was tested by the flame test the colorindicated the presence of a considerable amount of sodium. Thecolor was much more marked than with cane sugar of the samestrength. Dr. Stieglitz kindly analyzed the solution for me andfound it contained considerable sodium chloride. Throue^h the. ([jfj«.^\,^w--— Figure 1. — Illustrates the nature and extent of a rhythm established in a solution ofso-called chemically pure dextrose. This and subsequent tracings should be readfrom left to riffht. kindness of Professor Nef I secured a sample of crystallifie solution of this was as clear as distilled water and showed whentested no trace of sodium chloride. Stiips of ventricle wJien placedin it did not beat rhythmically nor would they make even single con-tractions. The only change was an increase in tone of the strip. Itis possible that those who have obtained rhythmic beats from stripsin dextrose solutions did not use the crystalline form of the sugar,and so really worked with a dilute solution of sodium chloride indextrose. The crystalline dextrose solution, like the cane sugarsolution, does not kill the heart tissue for some time, and strips thatwill not beat in it can be made to do so by putting them into a solu-tion of sodium s
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