Text-book of botany, morphological and physiological . jacent cells of two moreor less parallel filaments. A preparation is made for it by the formation of lateralprotuberances, as represented in Fig. 5, a ; these continue to grow until theymeet {b). The protoplasm-sac of each cell concerned then contracts; it detachesitself sharply from the surrounding cell-wall; rounds itself into an. ellipsoidal form,and contracts still more by expulsion of the water of the cell-sap. This occurssimultaneously in the two conjugating cells. Next the cell-wall opens between thetwo protuberances (Fig. 6, a), an
Text-book of botany, morphological and physiological . jacent cells of two moreor less parallel filaments. A preparation is made for it by the formation of lateralprotuberances, as represented in Fig. 5, a ; these continue to grow until theymeet {b). The protoplasm-sac of each cell concerned then contracts; it detachesitself sharply from the surrounding cell-wall; rounds itself into an. ellipsoidal form,and contracts still more by expulsion of the water of the cell-sap. This occurssimultaneously in the two conjugating cells. Next the cell-wall opens between thetwo protuberances (Fig. 6, a), and one of the two ellipsoidal protoplasmic bodiesforces itself into the connecting channel thus formed ; it glides slowly through itinto the other cell-cavity, and as soon as it touches the protoplasmic body con-tained in it, they coalesce (Fig. 6, a). After complete union (Fig. 6, b) the unitedbody is again ellipsoidal, and scarQely larger than one of the two which composeit ; during the union a contraction has evidently taken place with expulsion of. Fig. 4.—A, B escape of the swarm-sporesof an Oedog^onium; C one free in motion ;D the same after it has become fixed andhas formed the attaching disc ; E escapeof the whole protoplasm of a germ-plant ofOedogonium in the form of a swarm-spore(X350). (After Pringsheim, Jahrb. fijr I. pi. I.) lO MORPHOLOGY OF THE CELL. water. The coalescence gives the impression of a union of two drops of fluid ; butthe protoplasm is never a fluid; and, independently of other circumstances, there isa fact that shows that altogether peculiar forces are here active which are absent fromall fluids;—the spiral band of chlorophyll of each of the two conjugating protoplasmicbodies is preserved in the contraction; it only becomes closely drawn together; during
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
