. The cytoplasm of the plant cell. Plant cells and tissues; Protoplasm. GuilHermond - Atkinson —10 — Cytoplasm then, under its immobile surface, flows with extreme rapidity. In addition, the different veins and the flowing, continuous layers com- prising the Plasmodium, show very curious, rhythmic but not syn- chronous, pulsations. These are rendered quite visible by motion- picture photography. Each vein shows an alternation of systole and diastole; each outer layer flows by jerks over the substratum, becoming alternately thicker and thinner (CoMANDON and PiNOY, Seifriz). Under sufficiently h
. The cytoplasm of the plant cell. Plant cells and tissues; Protoplasm. GuilHermond - Atkinson —10 — Cytoplasm then, under its immobile surface, flows with extreme rapidity. In addition, the different veins and the flowing, continuous layers com- prising the Plasmodium, show very curious, rhythmic but not syn- chronous, pulsations. These are rendered quite visible by motion- picture photography. Each vein shows an alternation of systole and diastole; each outer layer flows by jerks over the substratum, becoming alternately thicker and thinner (CoMANDON and PiNOY, Seifriz). Under sufficiently high magnification the Plasmodium seems to be formed of an homogeneous substance, holding in suspension in- numerable granules, in particular, lipide droplets and ingested debris, whose incessant displacement in different directions reveals with great clearness the existence of cytoplasmic currents. These currents are very irregular. They may be rapid or may even rush along in a vein and, at a given instant, V\ /# they will immediately slow up, then change direc- ^ " tion, accelerate, retard again, return to the orig- inal direction and so on. In each vein the same irregularities are observed but without any syn- chronism whatever. Thus, the movement of the entire mass of the Plasmodium in one direction expresses the sum of all these movements in dif- ferent directions and indicates that in this appar- ent disorder, the protoplasm flows more in one direction than in the other; namely, in the direc- tion of the advance of the organism. Now these characteristics of protoplasm have nothing unusual about them. Microscopical ex- of the diff^enrdire™ aminatious of the contents of the most varied cells tions taken by proto- reveal that there, too, protoplasm behaves as a plasmic currents in a ^ . , , , mi it i • i -x i i i portion of the vein- fluid substance. The bodies which it holds sus- piTsmodium.'"" °^ ^ pended in it are in most cases more or less rapidly
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Keywords: ., bookcentury1900, bookcollection, booksubjectplantcellsandtissues
