General physiology; an outline of the science of life . TIMULI AND THEIR ACTIONS 411 current. Hence, an essential difference between the making andthe breaking induction-shocks is observed in the secondary coil,since with the former, on account of the slow increase of theprimary current, the electric tension is more gradually equalisedthan with the breaking shock, where the equalisation takes placevery suddenly. If, therefore, we wish to let a very sudden currentact upon a living object, we employ exclusively the breaking in-duction-shock. The intensity of the induction-shocks may begraduated
General physiology; an outline of the science of life . TIMULI AND THEIR ACTIONS 411 current. Hence, an essential difference between the making andthe breaking induction-shocks is observed in the secondary coil,since with the former, on account of the slow increase of theprimary current, the electric tension is more gradually equalisedthan with the breaking shock, where the equalisation takes placevery suddenly. If, therefore, we wish to let a very sudden currentact upon a living object, we employ exclusively the breaking in-duction-shock. The intensity of the induction-shocks may begraduated by the distance that is allowed between the primaryand the secondary coils. The intensity is less with greaterdistance, greater with smaller distance, and greatest when thesecondary coil, which is always made somewhat the larger, isshoved completely over the primary. The sledgc-inductorium of du Bois-Reymond, which is one ofthe most essential of all pieces of physiological apparatus, isconstructed, in accordance with the above principles, for the pro-. Fig. 195.—Jseefs or Wagners hammer. duction of induced currents ; in it the secondary coil slides upon asledge-like track (Fig. 196). It is arranged also to produce singleinduction-shocks rapidly and rhythmically. The contrivance thatmakes this possible is the Neef or Wagner hammer (Fig. 195),which is based upon the following principle. As is well known,the galvanic current has the peculiarity of transforming into amagnet a piece of soft iron, around which it flows, as long as thecircuit remains closed. If the current be broken, the magnetismdisappears. In Neef s hammer there is a brass column S, whichbears a straight spring. This spring, to the free end of whichis fastened a small hammer of soft iron, in its resting positiontouches an adjustable screw T, which is in connection with a wire P;the wire forms a coil about a soft iron rod which stands uprightunder the hammer, and ends in a second small brass column. Thetwo brass co
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Keywords: ., bookcentury1800, bookdecade1890, bookidgen, booksubjectphysiology
