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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    measurements was made, the measurements led to no rationalistic correlation between the process of regeneration and the mutila¬ tion of the organism, for the reason that there was no clear conception concerning the quantity which it was necessary to measure.1 This is only possible if we have a clear idea of the physico-chemical relation which it is intended or necessary to test. The writer has for a number of years conducted quantitative experiments on the regeneration of a plant, Bryophyllum caly- cinum, which have made it possible to correlate the process of regeneration with the quantity of chemical material. By compar¬ ing the dry weight of the regenerated shoots and roots with the dry weight of the leaves or stems which were used for regenera¬ tion, it could be shown that in the presence of light the quantity of regeneration was under equal conditions of illumination, temperature, and in equal time in direct proportion to the mass of the leaves or stems from which regeneration started. If we make the legitimate assumption that the material required for the formation of new shoots or roots was under the conditions of our experiments produced by the chlorophyll contained in the leaf or stem, it follows that the quantity of regeneration is deter¬ mined in this case by the mass of material available in the stem or leaf for synthetic processes. Under the guidance of this mass relation (which may be, in part at least, identical with the law of mass action), it could be shown that mutilation of the plant leads to a collection of sap in places where it would not have collected without the mutilation. This accounts for the fact that mutila¬ tion leads to growth in places of the organism where no growth would have occurred without mutilation. The process of regeneration was thus revealed as a purely physico-chemical 1 In addition to the literature mentioned in the text, the reader is referred to Barfurtii, D., Methodcn zur Erforschung der Regeneration bei Tieren, in Abderhalden’s Handb. biol. Arbeitsmeth., Abt. V, Teil 3, Heft 1, 1921, and Barfuuth’s and Driescii’s reviews of the literature in Ergcb. Anatom, u. Entwicklungsgcsch., Vol. xxii, 1914, and earlier volumes. Also Korsciielt, E., Regeneration und Transplantation, Jena, 1907; Przibram, II., Experimen¬ tal-Zoologic, ii, Regeneration, Leipzig and Wien, 1909. The most interesting recent publications on regeneration are from Przibram’s laboratory, by him¬ self and his collaborators. For the problem of growth which is fundamental for regeneration, the reader is referred to Robertson, T. B., “The Chemical Basis of Growth and Secenscence, Philadelphia and London, 1923.