The dynamics of living matter The dynamics of living matter . dynamicsofliving1906loeb Year: 1906 TROPISMS AND RELATED PHENOMENA 141 2. Galvanotropism When animals are exposed to a galvanic current, compulsory re- actions may occur which agree with the compulsory reactions produced by light, with the difference that we have to substitute the current curves for the light rays. When parallel current curves strike a sym- metrical organ or organism sidewise, the contractile elements, muscles, on one side of the organ, or organism, undergo a higher degree of tension than on the other side; th
The dynamics of living matter The dynamics of living matter . dynamicsofliving1906loeb Year: 1906 TROPISMS AND RELATED PHENOMENA 141 2. Galvanotropism When animals are exposed to a galvanic current, compulsory re- actions may occur which agree with the compulsory reactions produced by light, with the difference that we have to substitute the current curves for the light rays. When parallel current curves strike a sym- metrical organ or organism sidewise, the contractile elements, muscles, on one side of the organ, or organism, undergo a higher degree of tension than on the other side; the outcome is a bending or turning of the organ or animal until its axis, or plane of symmetry, is in the direction of the current curves. As soon as this occurs, the symmet- rical elements of the surface of the body are struck at the same angle by the current curves and the kind and acceleration of chemical re- action is the same on both sides of the organism; consequently the symmetrical muscle elements show the same state of contraction. But the fact that the current curves penetrate throughout the whole animal causes often complications which prevent an ideal orientation such as we observe in the case of light. A most striking case of galvanotropism was found recently by Ban- croft * m Poly orchis penicillata, a Medusa. 'The method of experi- mentation consisted in cutting the Medusa in various ways, and placing the pieces in a trough of sea water through which the galvanic current was conducted with non-polarizable electrodes. The current strength varied from 25 to 2008. The responses were usually distinct with 258, but became more decided as the current was increased. 'If a meridional strip (Fig. 28) passing from the edge on one side through the center of the bell to the other edge be prepared and the current passed through transversely, tenta- cles and manubrium turn and point toward the cathode (Fig. 28). A reversal of the current initiates a turning of these organs in t
Size: 1363px × 1467px
Photo credit: © Bookend / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
