On the circumstances which modify the action of caffeine and theine upon voluntary muscle / by T. Lauder Brunton and J. Theodore Cash.

  • Brunton, Thomas Lauder, Sir, 1844-1916.
Date:
[1888]
Catalogue details

Licence: Public Domain Mark

Credit: On the circumstances which modify the action of caffeine and theine upon voluntary muscle / by T. Lauder Brunton and J. Theodore Cash. 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.

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    It will be observed that although the curve is entirely sub-abscissal there i.s at first a relaxation, then a distinct rise, and finally at the end of the record a more marked relaxation. In this instance then there is no evidenu; of positive shortening of the muscle and nothing approaching a condition of rigor. T. (Fig. 8). For the second ex})eriinent we have chosen a curve which illustrates a different rhythm and a sslight permanent contraction of the mnscle whicli Jb'io. 8. T. Comparative action of tlieine and caffeine. The curve has been divided into three parts for convenience of printin<^ and the marks + and % iu- dicate where the parts are continuous. The upper line in each is the caffeine curve and the lower the theine curve. was not seen in S. The frog the muscles of which we employed was an animal of 20 grannnes weight caught 10 days previously, and kept in the laboratory for some days. The solutions we employed were exactly similar to those used in experi- ment S. The only result observed in the case of the muscle suspended in caffeine solution, was a very slight tonic contraction commencing 8 hours 15 minutes after immei-sion, and amounting to 125. With the muscle suspended in theine the case was different, faint contractions and relaxations soon making their appearance after the ad- mission of the solution (containing •027 grm. theine) to the muscle chamber. As it occurred to us that tension exerted at the time when a contraction or shortening would follow in course might modify the rhythm, we kept the lever steadily depressed for 2 minutes during such a time. On releasing