. The Protozoa. Protozoa. is poured out upon the free surface of the protoplasmic body, where it produces a local diminution of surface tension, and in this way sets up an extension centre together with forward ;1 The origin of a pseudopodium, according to this conception, is in the ectoplasm, and the rapidity of a pseudopodium-formation is increased by the peculiar "fountain currents" char- acteristic of most pseudopodia. As observed by Butschli, an advancing stream of granules flows through the centre or axis of the growing pseudopo- dium, while near the tip back-runn
. The Protozoa. Protozoa. is poured out upon the free surface of the protoplasmic body, where it produces a local diminution of surface tension, and in this way sets up an extension centre together with forward ;1 The origin of a pseudopodium, according to this conception, is in the ectoplasm, and the rapidity of a pseudopodium-formation is increased by the peculiar "fountain currents" char- acteristic of most pseudopodia. As observed by Butschli, an advancing stream of granules flows through the centre or axis of the growing pseudopo- dium, while near the tip back-running currents like the falling drops of water in a fountain surround the central stream (Fig. 47). " In the formation of a —Diagram finger-shaped pseudopodium of Amceba proteus," says °fthe movements of -j, , .. . , , . the endoplasm gran- butschu, it can be seen that the current which uies in an advanc- traverses the axis of the pseudopodium and flows ins pseudopodium n • 1 r .. of Amceba proteus. away on all sides from its tip, comes to rest at a [butschli.] very short distance behind the tip, — a circumstance which in any case is extremely favorable to the rapid outgrowth of the pseudopodium, in contradistinction to the relations that obtain in the drops of foam, since the protoplasm that has come to rest is heaped up and the pseudopodium grows in this ;2 Rhumbler ('98) attempts to explain the formation of new ectoplasm and the increase in surface of an advancing pseudopodium through the hardening effect of water upon protoplasm, a fact which has long been recognized (Butschli, Pfeffer). An advancing pseudopodium of Amceba proteus, if properly fixed and stained, shows an advanced mass of endoplasm broken through the walls of The outer ectoplasm has a firm consistency, and, as Rhumbler dem- onstrated by treatment with diluted caustic potash (Fig. 48), may be isolated from the endoplasm. Nevertheless, it is converted into streaming e
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Keywords: ., bookauthorcalkinsg, bookcentury1900, bookdecade1900, bookyear1901
