. Elements of human physiology. Physiology. THE CONTRACTILE TISSUES 143 a tetanus obtained by discontinuous stimulation. If stronger solutions be used, the action of the drug is apt to affect the fibres unequally, so that we may have a sharp normal twitch preceding the prolonged contraction (Fig. 64). If the muscle Fi<;. (33. A. Tracing of the contraction of a frog's sartorius, poisoned with veratrin, in response to a momentary stimulus. The time- marking indicates seconds. B. Tetanic contraction of normal sartorius in response to rapidly interrupted stimuli. (The duration of the stimulus i
. Elements of human physiology. Physiology. THE CONTRACTILE TISSUES 143 a tetanus obtained by discontinuous stimulation. If stronger solutions be used, the action of the drug is apt to affect the fibres unequally, so that we may have a sharp normal twitch preceding the prolonged contraction (Fig. 64). If the muscle Fi<;. (33. A. Tracing of the contraction of a frog's sartorius, poisoned with veratrin, in response to a momentary stimulus. The time- marking indicates seconds. B. Tetanic contraction of normal sartorius in response to rapidly interrupted stimuli. (The duration of the stimulus is indi- cated by the words ' on' and ' off.') It will be noticed that the two curves are practically identical. (Miss Buchanan.) be excited immediately after the prolonged contraction has passed away, it responds with a single twitch like a normal muscle, but if allowed to rest a few minutes, stimulation is again followed by the peculiar long drawn out contraction. Fig. Excitation. 'uvj"^\' Seconds. Tracing of the contraction of a muscle poisoned by the injection of a strong solution of veratrin, showing the double contraction due to unequal poisoning of different fibres. (Biedermann.) The action of sodium salts on muscle is of considerable interest. We are accustomed to use a 0*6 per cent, solution of NaCl as a ' normal fluid' to keep muscle preparations. 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 Starling, Ernest Henry, 1866-1927. Chicago : W. T. Keener
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