. Comparative physiology. Physiology, Comparative; Physiology, Comparative. CILIARY ACTIVITY 39 specific action of the added substance in either direction can be conveniently observed. He recommends the following formula for Fundulus : 6 vols. N/io NaCl, i vol. N/10 KCl, 0*35 vol. N/io CaClg. The most remarkable result which emerges in this con- nection from Spaeth's experiments is the effect of barium salts, which, as is well known, exercise a very characteristic excitatory action upon true contractile tissues. After treatment of scales for ten minutes in N/io BaCl2 no sign of recovery may ap
. Comparative physiology. Physiology, Comparative; Physiology, Comparative. CILIARY ACTIVITY 39 specific action of the added substance in either direction can be conveniently observed. He recommends the following formula for Fundulus : 6 vols. N/io NaCl, i vol. N/10 KCl, 0*35 vol. N/io CaClg. The most remarkable result which emerges in this con- nection from Spaeth's experiments is the effect of barium salts, which, as is well known, exercise a very characteristic excitatory action upon true contractile tissues. After treatment of scales for ten minutes in N/io BaCl2 no sign of recovery may appear for as much as half an hour, during which the melanophores remain completely contracted. After this period of quiescence, the melanophores in the periphery of the scale abruptly expand. Fig. 14.—Melanophores of Fundulus (Spaeth). Effect of adrenaline {a) on the partially contracted pigmentary effectors (b) ; effect of adrenaline after previous immersion in ergotoxine (c). and contract almost at once. After a brief interval a second expansion wave appears at the periphery, and melanophores lying nearer the centre begin to behave in a similar manner. This time, however, the peripheral melanophores expand more completely. Eventually after about an hour the wave of rhythmic expansion and contraction extends to the centre of the scale so as to include all the melanophores, which pulsate between the extremes of contraction and complete expansion. This pulsation may continue for several hours. The Crustacean chromatophore consists essentially of a centre, branches radiating therefrom in a luxuriantly ramifying system. In the aduh forms of most Crustacea which have been. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hogben, Lancelot Thomas, 1895-. New York, The Macmillan Company
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