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7. Theory of Growth, Reproduction, Sex, and Heredity

Published online by Cambridge University Press:  15 September 2014

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Extract

From the synthetic outline of the history of biology contained in a previous paper, the practical corollary was deduced, that it was now legitimate, if not indeed urgent, for the biologist to reverse the usual order of investigation, and instead of merely adding inductively to the categories (therein enumerated) of accumulated fact, boldly to set about interpreting these in terms of their fundamental secret, that of constructive and destructive metabolism—anabolism and katabolism.

Type
Proceedings 1885-86
Copyright
Copyright © Royal Society of Edinburgh 1886

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References

note * page 911 As already noted in the previous paper, the physiologist no longer seeks to explain function in terms of organisation, but rather both in terms of protoplasm. It is thus necessary to postulate an acquaintance with the modern conception of protoplasm, for which reference may be made to M. Foster's Ency. Brit, article on “Physiology,” and the writer's article on “Protoplasm.” The general theory may be summarised in the accompanying diagram. Protoplasm is regarded as an exceedingly complex and unstable compound, undergoing continual molecular change or metabolism. On the one hand, more or less simple dead matter or food passes into life by a series of assimilative, ascending changes, with each of which it becomes molecularly more complex and unstable. On the other hand, the resulting protoplasm is continually breaking down into more and more simple compounds, and finally into waste products. The ascending, synthetic, constructive series of changes are termed “anabolic,” and the descending, disruptie series, “katabolic.” Both processes may be manifold, and the predominance of a particular series of anabolic or katabolic changes implies the specialisation of the cell. The upper figure (A) represents the complex unstable protoplasm as if occupying the summit of a double flight of steps ; it is formed up the anabolic steps, it breaks up and descends by the katabolic. The lower figure (B) is a projection of the upper, its convergent and divergent lines serving to represent the various special lines of anabolism and katabolism respectively, and the definite component substances (“anastates” and “katastates”) which it is the task of the chemical physiologist to isolate and interpret.

note * page 912 “Reproduction” and “Sex,” Ency. Brit., vols. xx. and xxi.

note † page 912 Principles of Biology.

note * page 917 “Sexuality of Fungi,” Quart. Jour. Micr. Sei., xxiv.

note * page 922 See “Sex,” Ency. Brit.

note * page 924 History and Theory of Spermatogenesis,” Geddes, and Thomson, J. Arthur, Proc. Roy. Soc. Edin., 1886.Google Scholar

note * page 930 See “Variation and Selection,” in forthcoming volume of Ency. Brit.