This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 edition. Excerpt: ...falls to 10, while the right end is at 25, the Paramecia migrate to the right end. Towards a temperature of 25 Paramecium is thus positively thermotactic (Fig. 72, ?). Finally, if cold water be passed through the tube at one.end of the trough and hot water at the other, the organisms will be found ...
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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 edition. Excerpt: ...falls to 10, while the right end is at 25, the Paramecia migrate to the right end. Towards a temperature of 25 Paramecium is thus positively thermotactic (Fig. 72, ?). Finally, if cold water be passed through the tube at one.end of the trough and hot water at the other, the organisms will be found accumulated in the middle of the trough where the temperature ranges from 24 to 28 C. This temperature is thus the optimum temperature for Paramecium, the temperature towards which it tends to move when the extremes are offered to it. Using another nomenclature, we may say, Paramecium is attuned to a temperature of 24 to 28 C., and tends to keep in the temperature to which it is attuned. Similar results have been obtained by DE Wildemann ('94) from Eugleiite which were kept in damp sand and in the dark, in a horizontal test-tube warmed at one end. Under these conditions they migrated towards the temperature of 30 rather than that of 15 to 22. Finally, we may consider thermotaxis as it is revealed in the higher animals. Loeb ('90, p. 43) enclosed the larvae of the bombycid moth Porthesia in an opaque box, one end of which-was next the stove. The animals moved to the warmer end of the box. The migration differed, however, from migrations with reference to light in that the body was not definitely oriented with reference to the source of heat, but the larvae wandered thither. Similarly some ants (Formica sanguinea) are thermotactic according to Wasmann ('91, p. 22); and the cockroach (graber, '87, p. 254) moves towards that temperature which is more nearly normal for it. Graber ('83, p. 230) has likewise shown that the salamander Triton is similarly responsive. Thus some Metazoa as well as Protista are clearly thermotactic. Looking now for the cause...
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