General physiology; an outline of the science of life . substance,is shown by the simple factthat in Actinosphcerium, Or-bitolitcs, and Amphistegina, itis not present; in these formsan excitation of contractionalone appears at both theanode and the kathode. In summarising briefly ourknowledge of the polar effectsof the galvanic current, it canonly be said that the primaryeffects of the constant currentare localised at the points ofentrance into (anode) and exitfrom (kathode) the living sub-stance ; in the different formsof living substance the kindof excitation at the kathodeand at the anode u
General physiology; an outline of the science of life . substance,is shown by the simple factthat in Actinosphcerium, Or-bitolitcs, and Amphistegina, itis not present; in these formsan excitation of contractionalone appears at both theanode and the kathode. In summarising briefly ourknowledge of the polar effectsof the galvanic current, it canonly be said that the primaryeffects of the constant currentare localised at the points ofentrance into (anode) and exitfrom (kathode) the living sub-stance ; in the different formsof living substance the kindof excitation at the kathodeand at the anode upon making and upon breaking are verydifferent; hence, no general law of polar excitation, applicable toall living substance, can be formulated. We will here leave the polar effects of the galvanic current andtake up the various kinds of excitation-phenomena caused byelectric stimulation. The effects upon contractile substances havealready been considered to some extent. Contractile effects thatare manifested outwardly in motion will now be Fig. 203.—Tradesccuitia virginica. A cell from astamen-hair. A, Unstimulated ; B, stimulatedby an induction-current. The protoplasm hasflowed together into globules and lumps ata,b,c,d. (After Kiihne.) STIMULI AND THEIR ACTIONS 423 Expansion-effects of galvanic stimulation are mostly incon-spicuous externally, and it has already been seen that only incertain cases is it possible to observe them at all. But contraction-effects are everywhere noticeable. Typical phenomena of contrac-tion have already been seen in Actinosjjhcerium and AmpMstegina inthe formation of globules and spindles in the protoplasm of stimu-lated pseudopodia. Amoeba and leucocytes, as Golubew (68) andEngelmann (69) have shown, when acted upon by single induction-shocks, draw in their pseudopodia and assume a spherical protoplasm of plant-cells, as Klihne (64) demonstrated inthe cells of the stamen-hairs of Tradcscantia virginiea, is inducedlikewise
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