. General physiology; an outline of the science of life. 368 GENERAL PHYSIOLOGY brought into contact with these stimuli, likewise gradually draws in its pseudopodia, the protoplasm becoming contracted into numerous,small globules and spindles, which slowlyflowcentripetally into the cell-body i (Fig. 159). Upon the effect of chemical stimuli upon ciliary motion, Engelmann (79, 1) and Rossbach (71) especially have carried out detailed investigations. Here also the greatest variety of sub- stances, such as acids, alkalies and salts, carbonic acid and various alkaloids, have like effects, which al
. General physiology; an outline of the science of life. 368 GENERAL PHYSIOLOGY brought into contact with these stimuli, likewise gradually draws in its pseudopodia, the protoplasm becoming contracted into numerous,small globules and spindles, which slowlyflowcentripetally into the cell-body i (Fig. 159). Upon the effect of chemical stimuli upon ciliary motion, Engelmann (79, 1) and Rossbach (71) especially have carried out detailed investigations. Here also the greatest variety of sub- stances, such as acids, alkalies and salts, carbonic acid and various alkaloids, have like effects, which always consist in an augmentation of the activity of the cilia or flagella, the rate of their beat being considerably increased. The result is a considerable augmentation of the motor effect, which can be clearly observed in free-living ciliated cells, such as Infusoria, in a great acceleration of their. Fig. 159.—Actinospliarlum under cJiemical stimulation. A, Unstimulated ; B, at the beginning of the stimulation; C, after the stimulation has continued for some time (the pseudopodia are almost entirely drawn in). motion. After the addition of chemical reagents the Infusoria by the strokes of their cilia rush madly through the field of view. Numerous chemical stimuli act upon the different forms of muscle-fibres (myoids, smooth muscle-fibres, cross-striated muscle- fibres) in a manner analogous to that upon naked protoplasmic masses, by calling out contractions. If to a drop of water in which many Vorticellce exist, waving their bodies gracefully upon their extended stalk-muscles, chemical substances of the above-mentioned kinds be added, all the Voriicello} immediately draw together, their stalk-muscles suddenly contracting in their elastic sheaths, and coiling up into delicate spirals (Fig. 160, h). Gross-striated muscles likewise contract suddenly upon chemical stimulation. If, , the sartorius muscle of a frog, which forms a small band of nearly parallel, cross-striated
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