Regeneration from a physico-chemical viewpoint / by Jacques Loeb.

  • Loeb, Jacques, 1859-1924.
Date:
1924
Catalogue details

Licence: In copyright

Credit: Regeneration from a physico-chemical viewpoint / by Jacques Loeb. Source: Wellcome Collection.

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    When merely a lateral incision is made through the body wall of Cerianthus (abc, in Fig. G), tentacles will grow out from the lower edge be of the cut. No growth of tentacles will occur from the other end, ab, and only the ordinary process of wound healing will take place here as a consequence of which the incision will be closed. The body of the animal will look after some time as in Fig. 7. The sea water does not contain the material for the formation of the new tentacles. The tentacles are formed from material contained in the tissue sap which surrounds the cells and soluble material in this sap is synthesized by an action inside the cells Fig. 7. Fig. 6. Figs. 6 and 7.—Effect of lateral incision into the body of the actinian. Only the lower edge be of the incision abc forms tentacles. into the solid material forming the regenerated tentacles. Since the chromosomes of the nucleus determine the hereditary form their chemical constitution must in some way be responsible for the formation of tentacles in the regenerating piece. As a second type may be selected the regeneration of fresh water planarians studied by Morgan.1 When a piece, aedb (Fig. 8), is cut out from a planarian at right angles with the longi¬ tudinal axis of the animal the piece will regenerate a new head in front of ac, a new tail at the other end, db, and an organism as represented in Fig. 9 will result. When, however, the piece aedb is cut out obliquely from the body (Fig. 10) a tiny new head will be formed only in the foremost corner a, and a tiny new tail in the hindmost end b (Fig. 11). This type of regeneration differs typically from that of Cerianthus in that the regeneration is no longer the same for each longitudinal element but depends upon 1 Morgan, T. It.: “Regeneration,” New York, 1901.