Licence: Public Domain Mark
Credit: Structure and functions of the brain and spinal cord. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![rendered still more obvious by the observation of Einier. that if a maroinal bodv and surroundinof part of the umljrella or bell be excised and placed in suitable innocuous fluid, the part will rh^-thmically contract f jr ten days or more. 2. ArtificialProcluction.—The further analysis of the rh}-thm was wanting, until Mr. Romanes pro- ceeded to investigate the possibilitv of reproducing it m the paralysed bell of the medusa. This he found to be actually possible by exciting the motion- less tissue with either a faradaic electric current or a chemical irritant Hke o-lvcerme. The result was to evoke a remarkably regular rli^thmical contraction and relaxation of the tissue. Such a re-awakening of the lost rhythm is a very remarkable fact, but its full discussion we must postpone for the moment. However, there is an all-important corol- larv to this experiment—namely, the question of fatigue. How far this element is present in relation to such a condition, and, if present, how far it goes to reveal the origin and natui'e of the (artificial) rhythm, must now be considered. ]\Ii\ Romanes found that if he caused the rhvthmical movements to inscribe themselves bv then- raisincr a licrht lever which could write on a blackened moving surface, the result was a wavy line, as shown in Fig. 8 ; if then the piece of tissue were electricallv excited for](https://iiif.wellcomecollection.org/image/b21218262_0058.jp2/full/800%2C/0/default.jpg)
