Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Credit: The collected papers of Sydney Ringer. Source: Wellcome Collection.
Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.
33/538 (page 15)
![conivactilitv stiJl persisls, and stimulating the musele with a iaradic current the coil, standing at 15 to 20, will excite good contractions. Moreover, tlu‘ addition of suhstances like barium chloride at once developes active contraction; indeed hariuni chloride ^^'ill produce con- tractions and ])ersistent spasms mucli more marked than with saline at tlie beginning of the experiment.’ ‘ I made twelve experiments to test also the eftect of calcium chloride using 1 per cent, solution. 1 added 2 to 4 c.c. of this to 200 c.c. of saline solution. After testing the eftect of simple saline I added at once 4 c.c. of calcium chloride solution. In every instance I tried this solution t' it almost immediately to a great extent lessened the contractions, and in many instances all but arrested them, in some, quite stopped them. Ill seyeral cases after a few minutes slight contractions returned hut were much less than with saline at the beginning of the experiment. In eight of the experiments at one period after the addition of lime chloride the contraction became literally rhj^hmic, i.e., the contraction occurred at pretty equal interAuils and in much the same force. The following short account of an experiment is a good example of the experiments. On April 5 the sartorius in saline contracted actiyely. The addition of 4 c.c. of CaCl2 solution at once almost arrested the con- tractions which were rhythmic in character. I then returned to saline solution, which induced actiye contractions, and these were at once arrested on the addition of 4 c.c. of calcium chloride solution. Again I placed the muscle in simple saline and again actiye contractions occurred, which were at once arrested on adding 4 (*.c. of 1 per cent, solution of potassium chloride. The addition of lime chloride arrests not only the rapid contractions but also remoyes the persistent contraction, so that the trace rises highei- above the base line. These effects are shown in fin*, o. O In many experiments made with potassium chloride I find its action is largely influenced by temperature. My experiments have been made generally with the fluid at from 10° to 16° C. Soon after adding 4 c.c. of 1 per cent, solution of KCl to 200 c.c. saline solution the muscle strongly contracts, dragging down the recording lever far below the level reached even when the contractions are well marked with saline; the muscle then slowly relaxes, but before it has much elongated fresh con- tractions set in, or when at its maximum contraction frequent well marked contractions occur, nnd these cease and the muscle slowly relaxes, see fig. 4. Then the muscle remains quiescent for a variable](https://iiif.wellcomecollection.org/image/b28036530_0001_0033.jp2/full/800%2C/0/default.jpg)
